ALSA: timer: Fix wrong instance passed to slave callbacks

ALSA: timer: Fix wrong instance passed to slave callbacks

Orabug: 23330850

[ Upstream commit 117159f0b9d392fb433a7871426fad50317f06f7 ]

In snd_timer_notify1(), the wrong timer instance was passed for slave
ccallback function.  This leads to the access to the wrong data when
an incompatible master is handled (e.g. the master is the sequencer
timer and the slave is a user timer), as spotted by syzkaller fuzzer.

This patch fixes that wrong assignment.

BugLink: http://lkml.kernel.org/r/CACT4Y+Y_Bm+7epAb=8Wi=AaWd+DYS7qawX52qxdCfOfY49vozQ@mail.gmail.com
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
(cherry picked from commit 47eef3475c5f3063fc20e938f2fe24cd84d731aa)

Signed-off-by: Dan Duval <dan.duval@oracle.com>