This patch changes the return type of snd_hdac_power_up/down() and
variants to pass the error code from the underlying
pm_runtime_get/put() calls.  Currently they are ignored, but in most
places, these should be handled properly.

As an example, the regmap handler is updated to check the return value
and accesses the register only when the wakeup succeeds.
Signed-off-by: Takashi Iwai <tiwai@suse.de>