ALSA: hda: Use STAC_DELL_M6_BOTH quirk for Dell Studio 1558

ALSA: hda: Use STAC_DELL_M6_BOTH quirk for Dell Studio 1558

commit 5c1bccf645d4ab65e4c7502acb42e8b9afdb5bdc upstream.

BugLink: https://launchpad.net/bugs/568600
The OR has verified that the dell-m6 model quirk is necessary for audio
to be audible by default on the Dell Studio XPS 1645.

This change is necessary for 2.6.32.11 and 2.6.33.2 alike.

Reported-by: Andy Ross <andy@plausible.org>
Tested-by: Andy Ross <andy@plausible.org>
Signed-off-by: Daniel T Chen <crimsun@ubuntu.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>