serial: imx: Fix warning when building 'allmodconfig'

When CONFIG_SERIAL_IMX_CONSOLE=n and CONFIG_CONSOLE_POLL=y we get the following
build warning:

drivers/tty/serial/imx.c:306:13: warning: 'imx_port_ucrs_save' defined but not used [-Wunused-function]
drivers/tty/serial/imx.c:315:13: warning: 'imx_port_ucrs_restore' defined but not used [-Wunused-function]

imx_port_ucrs_save/restore are only used under CONFIG_SERIAL_IMX_CONSOLE, so
their definitions should be also be protected only by CONFIG_SERIAL_IMX_CONSOLE.

This was detected when building 'allmodconfig'.
Reported-by: Olof's autobuilder <build@lixom.net>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/imx.c

@@ -302,7 +302,7 @@ static inline int is_imx6q_uart(struct imx_port *sport)
 /*
  * Save and restore functions for UCR1, UCR2 and UCR3 registers
  */
-#if defined(CONFIG_CONSOLE_POLL) || defined(CONFIG_SERIAL_IMX_CONSOLE)
+#if defined(CONFIG_SERIAL_IMX_CONSOLE)
 static void imx_port_ucrs_save(struct uart_port *port,
 			       struct imx_port_ucrs *ucr)
 {