Although we modified the codec shutdown callback to perform
runtime-suspend, it's still not fully effective, as this may be
resumed again at any time later.
For fixing such an unwanted resume, this patch replaces
pm_runtime_suspend() with pm_runtime_force_suspend(), and call
pm_runtime_disable() afterward. It assures to keep the device
suspended.
Also for code simplification, we apply the code unconditionally; when
it's been already suspended, nothing would happen by calls of
snd_pcm_suspend_all() and pm_runtime_force_suspend(), just proceed to
pm_runtime_disable().
As reboot_notify callback is no longer used by the codec core, let's
get rid of the unused code. Conexant codec needs a slight code change
as it used to call the reboot_notify at the codec removal, too.
So far we have a few workarounds at shutdown for each codec,
e.g. turning off the display power and setting the codec to D3.
But all those are basically a part of the suspend procedure.
Moreover, the streams are still active after that call, hence it might
hit the update on the codec that has been already put to D3.
In this patch, instead of calling each reboot_notify callback, simply
put the codec into the runtime-suspended state after the manual
suspend of all PCM streams. It makes the code and the behavior more
consistent.
The reboot_notify callback is no longer used after this patch, and
will be cleaned up later.
Conexant codecs have a workaround for the noise at shutdown to turn
off EAPD, but it wasn't applied at suspend. In the later patch, we'll
switch from reboot_notify callback to the general suspend-at-shutdown,
so let's apply the workaround to the suspend case, too.
