EXYNOS5: Enable console multiplexing in u-boot

We enable console multiplexing and use both serial and LCD for stdout/stderr.
Initially, u-boot output console is observed via serial port.
If you also have a DP panel connected onto your SMDK5250 board,
you can switch to LCD console by typing "setenv stdout lcd".
You can always switch back to serial using "setenv stdout serial".
You can switch error console(stderr) as well, using similar commands.

Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>

include/configs/exynos5250-dt.h

@@ -77,6 +77,17 @@
 #define CONFIG_BAUDRATE			115200
 #define EXYNOS5_DEFAULT_UART_OFFSET	0x010000
 
+/* Console configuration */
+#define CONFIG_CONSOLE_MUX
+#define CONFIG_SYS_CONSOLE_IS_IN_ENV
+#define EXYNOS_DEVICE_SETTINGS \
+		"stdin=serial\0" \
+		"stdout=serial,lcd\0" \
+		"stderr=serial,lcd\0"
+
+#define CONFIG_EXTRA_ENV_SETTINGS \
+	EXYNOS_DEVICE_SETTINGS
+
 #define TZPC_BASE_OFFSET		0x10000
 
 /* SD/MMC configuration */