arm: wandboard: move CONFIG_MXC_UART to defconfig

For using a debug UART on the Wandboard CONFIG_MXC_UART=y must be set in
the .config file.

To avoid duplicate definitions move the setting from
include/configs/wandboard.h to configs/wandboard_defconfig.

Document the debug UART settings in the README.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Reviewed-by: Fabio Estevam <festevam@gmail.com>

board/wandboard/README

@@ -37,3 +37,13 @@ as the mx6 processor)
 - Connect the serial cable to the host PC
 
 - Power up the board and U-Boot messages will appear in the serial console.
+
+Debug UART
+----------
+
+The following settings provide a debug UART for the Wandboard:
+
+CONFIG_DEBUG_UART=y
+CONFIG_DEBUG_UART_MXC=y
+CONFIG_DEBUG_UART_BASE=0x02020000
+CONFIG_DEBUG_UART_CLOCK=80000000

configs/wandboard_defconfig

@@ -67,6 +67,7 @@ CONFIG_PINCTRL_IMX6=y
 CONFIG_DM_PMIC=y
 CONFIG_DM_PMIC_PFUZE100=y
 CONFIG_DM_SCSI=y
+CONFIG_MXC_UART=y
 CONFIG_DM_THERMAL=y
 CONFIG_USB=y
 CONFIG_DM_USB=y

include/configs/wandboard.h

@@ -17,7 +17,6 @@
 /* Size of malloc() pool */
 #define CONFIG_SYS_MALLOC_LEN		(10 * SZ_1M)
 
-#define CONFIG_MXC_UART
 #define CONFIG_MXC_UART_BASE		UART1_BASE
 
 /* SATA Configs */