drivers/serial/ucc_uart.c: Add missing call to init UCC UART port timeout

The UCC UART driver is missing a call to uart_update_timeout().
Without this call, attempting to close the port after outputting large
amounts of data (i.e. using tty and uart buffering) results in long
timeouts before the port will actually be shut down.

For example, cat a large file to a UCC UART port.  With the current
driver, the port will stay open for 30 seconds after the last byte
of data is output.  But with this patch, the port is closed as
expected, just after the data has been output (tx fifos empty).

Signed-off-by: Chuck Meade <chuck@ThePTRGroup.com>
Acked-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>