ALSA: firewire-lib: include sound/asound.h to refer to snd_pcm_format_t
'snd_pcm_format_t' is used by amdtp_out_stream_set_pcm_format().
Currently, when just including amdtp.h, compiler cannot find this type because
this type is defined in uapi/sound/asound.h and this header is not included by
amdtp.h.