ALSA: hda - Fix unbalanced runtime PM refcount after S3/S4

commit e6bbe666673ab044a3d39ddb74e4d9a401cf1d6f upstream.

When a machine goes to S3/S4 after power-save is enabled, the runtime
PM refcount might be incorrectly decreased because the power-down
triggered soon after resume assumes that the controller was already
powered up, and issues the pm_notify down.

This patch fixes the incorrect pm_notify call simply by checking the
current value properly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>