ALSA: atiixp: Move PCM suspend/resume code into trigger callback

ATIIXP driver supports the full PCM resume and saves/restores the
running PCM pointer.  This used to be done in the suspend and resume
callbacks together with snd_pcm_suspend() call.  But since we moved
the snd_pcm_supsend*() call in PCM device PM ops, this should be moved
to a more appropriate place, i.e. the trigger callback.

Along with the movement of the PCM suspend/resume code, remove the
superfluous snd_pcm_suspend_all() call, too.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>