Inform userspace that one channel of the internal mic has reversed
polarity, so it does not attempt to add both channels together and
end up with silence.

Cc: stable@vger.kernel.org
Reported-by: NAndrzej Mendel <andrzej.mendel@gmail.com>
Alsa-info: http://www.alsa-project.org/db/?f=3088f82a0cf977855f92af9db8ad406c04f71efa
BugLink: https://bugs.launchpad.net/bugs/1529624Signed-off-by: NDavid Henningsson <david.henningsson@canonical.com>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>