MLK-10367-02 tty: serial: imx: set uart module clock to 80Mhz

When UART module clock is great than 80Mhz, there may have risk after
confirming with IC owner. So set the maximum module clock to 80Mhz.
(The patch just fix the first part that push un-correct patch version
by mistake)

Signed-off-by: Fugang Duan <B38611@freescale.com>
(cherry picked from commit: de250f6fb2e49504b839d2723ac289893475dbac)