ALSA: firewire-lib: localize kernel APIs to start/stop each AMDTP stream

As a result to support AMDTP domain, no drivers call kernel APIs to
start/stop each AMDTP stream. This commit localize these APIs.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>