We used to pass the power_save option value to hda_bus via a given
pointer.  This was needed to refer to the value from the HD-audio core
side.  However, after the transition to the runtime PM, this is no
longer needed.

This patch drops the power_save value indirection in hda_bus above,
and let the controller driver reprograms the autosuspend value
explicitly by a new helper, snd_hda_set_power_save().  Without this
call, the HD-audio core doesn't set up the autosuspend and flip the
runtime PM.  (User may still be able to set up via sysfs, though.)

Along with this change, the pointer argument of azx_bus_create() is
dropped as well.
Signed-off-by: NTakashi Iwai <tiwai@suse.de>