ALSA: hda - Add workaround for MacBook Air 5,2 built-in mic

commit 2ddee91abe9cc34ddb6294ee14702b46ae07d460 upstream.

MacBook Air 5,2 has the same problem as MacBook Pro 8,1 where the
built-in mic records only the right channel.  Apply the same
workaround as MBP8,1 to spread the mono channel via a Cirrus codec
vendor-specific COEF setup.

Reported-and-tested-by: Vasil Zlatanov <vasil.zlatanov@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>