This patch moves the suspend/resume mechanisms down to each codec
driver level, as we have a proper codec driver bound on the bus now.
Then we get the asynchronous PM gratis without fiddling much in the
driver level.

As a soft-landing transition, implement the common suspend/resume pm
ops for hda_codec_driver and keep the each codec driver intact.  Only
the callers of suspend/resume in the controller side (azx_suspend()
and azx_resume()) are removed.

Another involved place is azx_bus_reset() calling the temporary
suspend and resume as a hackish method of bus reset.  The HD-audio
core provide a helper function snd_hda_bus_reset() instead.

Signed-off-by: Takashi Iwai <tiwai@suse.de>