fireworks: Use __u32 instead of uint32_t for uapi

In a point of self-contained. And it's a way of Linux.

[alsa-devel] [PATCH 28/44] fireworks: Add command/response functionality into hwdep interface
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075176.html
fireworks: Add const type qualifier to PCM variables

According to maintainer's advice:
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075146.html
fireworks/bebob: Confirm to decrease reference counter for firewire unit.

amdtp_stream_init() increases the reference counter and amdtp_stream_destroy()
decreases it. This commit make it sure to decrease it.

According to maintainer's advice:
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075184.html
fireworks/bebob: Always success to stop streams

Even if transactions are disabled, the streams should be stopped.
This commit adds a pointer as a cache of master stream and remove
transaction from stream_stop_duplex().

According to maintainer's advice:
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075227.html
firewire-lib: Introduce AMDTP_IN_PCM_FORMAT_BITS for capture PCM format

According to maintainer's comment:
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075226.html
fireworks/bebob: Use atomic_t for substream counter

To keep consistency of counter even if instructions for incrementing /
decrementing the counter are preempted or performed by multi processes.

According to maintainer's advice:
[alsa-devel] [PATCH 24/44] fireworks: Add MIDI interface
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075112.html
fireworks/bebob: Fix PCM constraint for frames per period/buffer

According to maintainer's advice:
[alsa-devel] [PATCH 26/44] fireworks: Add PCM interface
http://mailman.alsa-project.org/pipermail/alsa-devel/2014-April/075146.html
fireworks/bebob: Simplify stream_start_duplex()

An argument for stream is needless. Reference counters can do the same work.
bebob: Improve return value of commands