ALSA: hda: Make snd_hdac_display_power() void function

After the recent refactoring, snd_hdac_display_power() doesn't return
any error, hence it can be defined to return void.
This makes many error checks redundant and allows us to reduce them
gracefully.

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