ALSA: hda - Fix missing inline for dummy snd_hdac_set_codec_wakeup()

This seems overlooked.

Fixes: 98d8fc6c ('ALSA: hda - Move hda_i915.c from sound/pci/hda to sound/hda')
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Takashi Iwai <tiwai@suse.de>