ALSA: aica: Fix a long-time build breakage

ALSA: aica: Fix a long-time build breakage

BugLink: https://bugs.launchpad.net/bugs/1863019
[ Upstream commit 534420c6ff87d3052540f1fd346e0adcff440819 ]

The build of aica sound driver has been broken since the timer API
conversion and some code rewrite.  This patch fixes the breakage by
using the common substream field, as well as a bit cleaning up wrt the
timer handling in the code.

Fixes: d522bb6a105f ("ALSA: sh: aica: Convert timers to use timer_setup()")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>