fireworks: add Echo Fireworks Command and Response

Fireworks uses its own system to command/response. Previously this is over
AV/C vendor dependent command but recent firmware don't use this type. Then
command to and response from specific addresses.

The address to receive response give us an issue. When this driver allocate its
own callback function into the address, then user-land implement cannot allocate
its own callback function via Juju interface. Currently this commit don't solve
this issue. This issue must be resolved in future.
fireworks: Add stream and connection management

Fireworks transmit/receive AMDTP stream with a few quirks and manage the
connection by CMP.
fireworks: Add proc interface for debugging

This commit add proc interface to output infomation for debugging.
 - hardware capabilities
 - clock
 - meters
fireworks: Add control interface

Currently supported controls are:
 - switching source of clock
 - change sampling rate
 - change S/PDIF format
 - change Digital interface mode

They are mainly for my debugging.
fireworks: Add MIDI interface

This commit adds the functionality to capture/playback MIDI message. MIDI
message is multiplexed/demultiplexed into AMDTP stream.
fireworks: Add PCM interface

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

PCM samples are multiplexed/demultiplexed into AMDTP stream safely with stream
helper functions.
fireworks: Add hwdep interface

This is for mixer/control application in user land. The application can
lock/unlock kernel streaming or get notification at starting kernel streaming
to use hwdep interface.