serial: imx: Move imx_port_ucrs_save/restore under CONFIG_CONSOLE_POLL

If CONFIG_CONSOLE_POLL is not defined, the following build warning happens:

drivers/tty/serial/imx.c:274:13: warning: 'imx_port_ucrs_save' defined but not used [-Wunused-function]
drivers/tty/serial/imx.c:283:13: warning: 'imx_port_ucrs_restore' defined but not used [-Wunused-function]

Move imx_port_ucrs_saver/restore under CONFIG_CONSOLE_POLL ifdef block to fix it.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>