serial: Kconfig: Add MXC_UART entry

Added kconfig for MXC_UART driver.

Cc: Simon Glass <sjg@chromium.org>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Peng Fan <peng.fan@nxp.com>
Cc: Matteo Lisi <matteo.lisi@engicam.com>
Cc: Michael Trimarchi <michael@amarulasolutions.com>
Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>

drivers/serial/Kconfig

@@ -309,6 +309,13 @@ config MVEBU_A3700_UART
 	  Choose this option to add support for UART driver on the Marvell
 	  Armada 3700 SoC. The base address is configured via DT.
 
+config MXC_UART
+	bool "IMX serial port support"
+	depends on MX6
+	help
+	  If you have a machine based on a Motorola IMX CPU you
+	  can enable its onboard serial port by enabling this option.
+
 config PIC32_SERIAL
 	bool "Support for Microchip PIC32 on-chip UART"
 	depends on DM_SERIAL && MACH_PIC32