oxfw: Add support for Behringer/Mackie devices

FFADO project have already identified that some devices produced by
Behringer/Mackie are based on OXFW970/971.

They support 'AV/C Stream Format Information' command. But some of them
don't implement 'LIST' subfunction. So this commit uses an assumption
that 'if they don't implement it, they don't change formation of stream
for each sampling rate'.

With this assumption, this driver generate formations for the devices by:
 1.getting current formation by SINGLE subfunction
 2.getting supported sampling rates
 3.applying current formation for all of supported sampling rates

Behringer/Mackie devices support capture/playback of PCM-samples and some
of them supports capture/playback of MIDI-messages. Followed commits will
add these functionalities.

temp
oxfw: Add support AMDTP in-stream and PCM capture

Previous commit adds support for some devices which can capture PCM samples.
They transmits AMDTP stream in non-blocking mode. This stream has a quirk fo
'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 handles both streams separately.

For your information, I note the sequence of CIP headers in stream transmitt
by  Behringer F-Control Audio 202:

When this driver gives no out-stream:
Index   Payload CIP_Header_0CIP_Header_1
38  14  00020092900103D1
39  12  00020098900102FF
40  12  0002009D9001027F
41  14  000200A290010396
42  14  000200A8900102E8
43  12  000200AE90010219
44  14  000200B390010331
45  12  000200B99001025F
46  14  000200BE90010376
47  12  000200C4900102A1
00  12  000200C99001023E
01  14  000200CE90010358
02  12  000200D490010289
03  16  000200D9900103A3
04  12  000200E0900102DD
05  14  000200E5900103F1
06  12  000200EB90010335
07  12  000200F090010263
08  14  000200F59001037C
09  12  000200FB900102AE

When this driver gives out-stream:
Index   Payload CIP_Header_0CIP_Header_1
38  12  000200BD900104A8
39  14  000200C2900104A8
40  12  000200C8900104AC
41  14  000200CD900104A9
42  12  000200D3900104B1
43  14  000200D8900104A8
44  12  000200DE900104AA
45  14  000200E3900104A9
46  14  000200E9900104AE
47  12  000200EF900104A8
00  14  000200F4900104AD
01  12  000200FA900104A7
02  14  000200FF900104A9
03  12  00020005900104A9
04  14  0002000A900104B1
05  12  00020010900104AA
06  14  00020015900104AD
07  12  0002001B900104A7
08  14  00020020900104AC
09  12  00020026900104A7
oxfw: Add support for capture/playback MIDI messages

I assume that 'if device formations of stream have MIDI conformant data
channels, the device has one MIDI port'. With this assumption, the driver
create MIDI devices.

When no streams have already started, MIDI functionality starts stream
with current sampling rate.

When MIDI functionality have already starts some streams and PCM
functionality is going to start streams at different sampling rate,
this driver stops streams once and changes sampling rate, then restarts
streams.
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.
bebob, fireworks: increment/decrement reference counter for unit
bebob: improve the way to parse stream information
oxfw: improve according to checkpatch.pl's advices
fireworks: fix forgetting to release lock
fireworks: arrange critical section for duplex streams