ALSA: HDA: Do not announce false surround in Conexant auto

Without this patch, one line-out and one speaker and
Conexant's auto parser would announce (non-working) surround
capabilities.

BugLink: http://bugs.launchpad.net/bugs/721126


Cc: stable@kernel.org
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>