[ALSA] hda-codec - Add Conexant 5051 codec support

Added the support for Conexant 5051 audio codec.
Right now there are two preset models, laptop and hp.
The whole patch is based on the information from the base patch by
Linuxant.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>