[ALSA] hda-codec - add support for swapping center/LFE channels to STAC codecs

Center/LFE channels are located on same jack, so it can be usefull
to swap them.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>