[ALSA] system timer: remove unused snd_timer_system_private.timer field

Remove the snd_timer_system_private structure's timer field that was never used.
Signed-off-by: NClemens Ladisch <clemens@ladisch.de>
Signed-off-by: NJaroslav Kysela <perex@suse.cz>

sound/core/timer.c

@@ -959,7 +959,6 @@ int snd_timer_global_register(struct snd_timer *timer)
 
 struct snd_timer_system_private {
 	struct timer_list tlist;
-	struct timer * timer;
 	unsigned long last_expires;
 	unsigned long last_jiffies;
 	unsigned long correction;