board: imx53: Always disable display before starting kernel

This patch prevents from the situation where we may end up with garbage
displayed on the LCD panel.

Such situation occurs when one performs "reboot -f" in Linux and then
stop in U-boot (or observe the garbage on the screen during boot up).

To prevent from such situation - the PWM pin is configured as GPIO and set
to LOW.

Signed-off-by: Lukasz Majewski <lukma@denx.de>

arch/arm/dts/imx53-kp.dts

@@ -86,6 +86,8 @@
 				MX53_PAD_PATA_DA_2__GPIO7_8 0x1e4
 				/* BOOSTER_OFF */
 				MX53_PAD_EIM_CS0__GPIO2_23 0x1e4
+				/* LCD BACKLIGHT */
+				MX53_PAD_GPIO_1__GPIO1_1 0x1e4
 			>;
 		};
 

board/k+p/kp_imx53/kp_imx53.c

@@ -22,6 +22,7 @@
 #define VBUS_PWR_EN IMX_GPIO_NR(7, 8)
 #define PHY_nRST IMX_GPIO_NR(7, 6)
 #define BOOSTER_OFF IMX_GPIO_NR(2, 23)
+#define LCD_BACKLIGHT IMX_GPIO_NR(1, 1)
 
 DECLARE_GLOBAL_DATA_PTR;
 
@@ -189,10 +190,17 @@ void eth_phy_reset(void)
 	udelay(50);
 }
 
+void board_disable_display(void)
+{
+	gpio_request(LCD_BACKLIGHT, "LCD_BACKLIGHT");
+	gpio_direction_output(LCD_BACKLIGHT, 0);
+}
+
 int board_late_init(void)
 {
 	int ret = 0;
 
+	board_disable_display();
 	setup_ups();
 
 	if (!power_init())