ARM: dts: imx6qdl-udoo: Properly describe the SD card detect

GPIO7_IO00 is used as SD card detect.

Properly describe this in the devicetree.

Fixes: 40cdaa542cf0 ("ARM: dts: imx6q-udoo: Add initial board support")
Signed-off-by: Fabio Estevam <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx6qdl-udoo.dtsi

···
  * Author: Fabio Estevam <[e-mail]>
  */
 
+#include <dt-bindings/gpio/gpio.h>
+
 / {
 	aliases {
 		backlight = &backlight;
···
 				MX6QDL_PAD_SD3_DAT1__SD3_DATA1		0x17059
 				MX6QDL_PAD_SD3_DAT2__SD3_DATA2		0x17059
 				MX6QDL_PAD_SD3_DAT3__SD3_DATA3		0x17059
+				MX6QDL_PAD_SD3_DAT5__GPIO7_IO00		0x1b0b0
 			>;
 		};
 
···
 &usdhc3 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_usdhc3>;
-	non-removable;
+	cd-gpios = <&gpio7 0 GPIO_ACTIVE_LOW>;
 	status = "okay";
 };