ALSA: Remove unneeded snd_pcm_substream.timer_lock

The timer callbacks are called in the protected status by the lock
of the timer instance, so there is no need for an extra lock in the
PCM substream.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/pcm.h

@@ -364,7 +364,6 @@ struct snd_pcm_substream {
         /* -- timer section -- */
 	struct snd_timer *timer;		/* timer */
 	unsigned timer_running: 1;	/* time is running */
-	spinlock_t timer_lock;
 	/* -- next substream -- */
 	struct snd_pcm_substream *next;
 	/* -- linked substreams -- */