We have two machines with alc256 codec in the pin quirk table, so
moving the common pins to ALC256_STANDARD_PINS.

Cc: stable@vger.kernel.org
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1447909


Signed-off-by: Hui Wang <hui.wang@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>