ALSA: hda: Explicitly permit using autosuspend if runtime PM is supported

This fixes runtime PM not working after a suspend-to-RAM cycle at least for
the codec-less HDA device found on NVIDIA GPUs.

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=207043
Signed-off-by: Roy Spliet <nouveau@spliet.org>
Link: https://lore.kernel.org/r/20200413082034.25166-7-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>