ALSA: hda - MacBookPro 5,3 line-in support

I've found the following patch is necessary to enable line-in on
my MacBookPro 5,3 machine.  With the patch applied I've successfully
recorded audio from the line-in jack.  This is based on the existing
5,5 support.

Signed-off-by: Vince Weaver <vweaver1@eecs.utk.edu>
Signed-off-by: Takashi Iwai <tiwai@suse.de>