[ALSA] oxygen: fix line-in recording selection

The GPIO pin 0 of the CM9780 must be set when muting the line input even
on non-Xonar cards.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>