ALSA: fix a typo during snd_assert() removal

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
diff --git a/sound/core/timer.c b/sound/core/timer.c
index b8ee49c..e582fac 100644
--- a/sound/core/timer.c
+++ b/sound/core/timer.c
@@ -306,7 +306,7 @@
 	struct snd_timer *timer = NULL;
 	struct snd_timer_instance *slave, *tmp;
 
-	if (snd_BUG_ON(!timer))
+	if (snd_BUG_ON(!timeri))
 		return -ENXIO;
 
 	/* force to stop the timer */