Revert "serial: imx: Move imx_port_ucrs_save/restore under CONFIG_CONSOLE_POLL"

This reverts commit cdc8da39.

In my attempt to fix a build warning on arm randconfig a build error on
imx_v6_v7_defconfig was introduced, so revert it for now.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>