BugLink: http://bugs.launchpad.net/bugs/1675327

Replace bitclock by mclk as PLL source to fix noise in audio output from
line-out jack.
Signed-off-by: Shrirang Bagul <shrirang.bagul@canonical.com>
Acked-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>