[ALSA] hda-codec - Conexant improvements

This patch further improves on the Conexant Audio driver.
Adds support for Fujistu Siemens Si1520 series laptops.
Adds support for mic/line in on CX20549 based systems (aka 5045).
removes duplicated or unused controls (gpio, spdif) from test model.

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>