serial: imx: Grab port lock in imx_uart_enable_wakeup()

The port lock needs to be held when doing read-modify-write on UCR1 and
UCR3.

Signed-off-by: Esben Haabendal <esben@geanix.com>
Link: https://lore.kernel.org/r/20240913-serial-imx-lockfix-v1-1-4d102746c89d@geanix.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>