ALSA: timer: Info leak in snd_timer_user_tinterrupt()

The "r1" struct has memory holes.  We clear it with memset on one path
where it is used but not the other.  Let's just memset it at the start
of the function so it's always safe.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>