[ALSA] hda-codec (realtek): add support for MacPro series workstations

This patch adds limited support for Intel-based MacPro workstations.
Currently, the front headphone jack is not functioning, but line out
and line in are working.  S/PDIF not tested.

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