HP dx2200 and dx2250 use Micro-Star International (MSI) motherboards
(models MS-7254 and MS-7297 respectively) with an ALC862 codec in
threestack configuration. Adding this quirk allows correct 5.1 sound
output in these systems.

Signed-off-by: Claudio Matsuoka <cmatsuoka@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>