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.

Signed-off-by: Takashi Sakamoto <[e-mail]>
Signed-off-by: Takashi Iwai <[e-mail]>

sound/firewire/amdtp.h

···
 #include <linux/err.h>
 #include <linux/interrupt.h>
 #include <linux/mutex.h>
+#include <sound/asound.h>
 #include "packets-buffer.h"
 
 /**