[ALSA] hda-codec - Fix logic error in headphone mute for Conexant codecs

This patch fixes a logic error introduced in the previous patch.
Without it, speaker automute mutes the speakers when headphones are
removed and unmutes when headphones are plugged in.
This was reported by Gregorio Guidi after getting the earlier patch
off this mailing list.

Signed-off-by: Tobin Davis <tdavis@dsl-only.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>