ALSA: timer: fix wrong comment to refer to 'SNDRV_TIMER_PSFLG_*'

ALSA timer core has a comment referring to 'SNDRV_MIXER_PSFLG_*' in
a definition of 'struct snd_timer_params' of UAPI header. I can see
this in initial state of ALSA timer core, at least in
'alsa-driver-0.4.0.tar.gz'.

This commit fixes the comment.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/uapi/sound/asound.h

@@ -752,7 +752,7 @@ struct snd_timer_info {
 #define SNDRV_TIMER_PSFLG_EARLY_EVENT	(1<<2)	/* write early event to the poll queue */
 
 struct snd_timer_params {
-	unsigned int flags;		/* flags - SNDRV_MIXER_PSFLG_* */
+	unsigned int flags;		/* flags - SNDRV_TIMER_PSFLG_* */
 	unsigned int ticks;		/* requested resolution in ticks */
 	unsigned int queue_size;	/* total size of queue (32-1024) */
 	unsigned int reserved0;		/* reserved, was: failure locations */