ALSA: hda - Don't power up when not powered down.

After cancel_delayed_work_sync returns, the power down work either never
started (power_on == 1) or finished (power_on == 0).  In the former case
there is no need to power up again.

Signed-off-by: Dylan Reid <dgreid@chromium.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>