oxfw: Add skelton for OXFW970/971 based devices

This commit add a new driver for BeBoB based devices with no functionality.
This driver just create/remove card instance according to callbacks.

OXFW970/971 are chipsets produced by Oxford Semiconductor for Multi-Channel
Isochronous Streaming FireWire Audio Controller.

Current supported devices:
 - Behringer F-Control Audio 202
 - Mackie Onyx-i series (former model)
 - Mackie Onyx Satellite

Devices possible to be supported if identifying IDs:
 - Mackie, d.2 pro
 - Mackie, d.4 pro
 - Mackie, U.420
 - Mackie, U.420d
 - Mackie, Tapco Link.Firewire/
oxfw: Read firmware version to name card

There is already an driver for OXFW970/971, snd-firewire-speakers(speakers.c).
But this driver aims to support recording equipment.

It's convinient to apply the same way for card name.
oxfw: Add some AV/C commands for channel formation of AMDTP stream

OXFW970/971 may supports AV/C Stream Format Information Specification 1.1
Working Draft (Apr 2005, 1394TA). So this driver uses 'EXTENDED STREAM FORMAT
INFORMATION' command.

This command has two subfunctions, SINGLE and LIST. To use SINGLE subfunction,
drivers can know current formation of AMDTP stream. To use LIST subfunction,
drivers can know all of available formations of AMDTP stream. But there are
some devices which don't implement LIST subfunction.

When device don't implement LIST subfunction, this driver assume formation of
AMDTP stream. The way of assumption is:
1.getting current formation with SINGLE subfunction
2.checking all of available sampling rate
3.applying current formation for all of available sampling rate

I note that this assumption is too bad when the device don't implement LIST
subfunction and different formation for AMDTP streams at every available
sampling rates. I believe this is rare.

This driver also uses another assumption for available MIDI ports. If one of
formations has MIDI conformant data channel, then this driver assume the device
has one MIDI ports. I believe it rare that device has several MIDI ports.
oxfw: Add connections and streams management

This commit adds management functionality for connections and streams.
OXFW970/971 use CMP to manage connections and uses AMDTP for streams.

They transmits AMDTP stream in non-blocking mode. This stream has a quirk for
'presentation timestamp'. The sequence of 'presentation timestamp' is invalid
even if header of packet shows 'CIP header with SYT field'. So this driver
can't reuse it for out-stream.

In this reason, this driver keep to send correct 'presentation timestamp' in
out-stream.

And I note that its fluctuation of 'presentation timestamp' is less when
out-stream exists (they receive AMDTP stream) than when no out-stream exists.

no out-stream exists:
Index	Payload	CIP_Header_0	CIP_Header_1
38	14	00020092	900103D1
39	12	00020098	900102FF
40	12	0002009D	9001027F
41	14	000200A2	90010396
42	14	000200A8	900102E8
43	12	000200AE	90010219
44	14	000200B3	90010331
45	12	000200B9	9001025F
46	14	000200BE	90010376
47	12	000200C4	900102A1
00	12	000200C9	9001023E
01	14	000200CE	90010358
02	12	000200D4	90010289
03	16	000200D9	900103A3
04	12	000200E0	900102DD
05	14	000200E5	900103F1
06	12	000200EB	90010335
07	12	000200F0	90010263
08	14	000200F5	9001037C
09	12	000200FB	900102AE

out-stream exists:
Index	Payload	CIP_Header_0	CIP_Header_1
38	12	000200BD	900104A8
39	14	000200C2	900104A8
40	12	000200C8	900104AC
41	14	000200CD	900104A9
42	12	000200D3	900104B1
43	14	000200D8	900104A8
44	12	000200DE	900104AA
45	14	000200E3	900104A9
46	14	000200E9	900104AE
47	12	000200EF	900104A8
00	14	000200F4	900104AD
01	12	000200FA	900104A7
02	14	000200FF	900104A9
03	12	00020005	900104A9
04	14	0002000A	900104B1
05	12	00020010	900104AA
06	14	00020015	900104AD
07	12	0002001B	900104A7
08	14	00020020	900104AC
09	12	00020026	900104A7
oxfw: Add proc interface for debugging purpose

This commit adds proc interface to get information for debugging.
 - stream formation
 - current sampling rate
oxfw: Add MIDI interface

This commit adds a functionality to capture/playback MIDI messages.

When no AMDTP streams are running, this module starts AMDTP stream at current
sampling rate for MIDI stream.
oxfw: Add PCM interface

This commit adds a functionality to capture/playback PCM samples.

Currently this driver has no functionality to check current source of clock.
When AMDTP stream is already running for PCM, available sampling rate is
limited at current one.
oxfw: Add hwdep interface

This interface is designed for mixer/control application. To use hwdep
interface, the application can get information about firewire node, can
lock/unlock kernel streaming and can get notification at starting/stopping
kernel streaming.