ARM: dts: socfpga: Add SD card detect

Revision D of the SOCFGPA devkit has a GPIO line used for SD/MMC card detect.
Signed-off-by: NDinh Nguyen <dinguyen@opensource.altera.com>
Acked-by: NPavel Machek <pavel@denx.de>

arch/arm/boot/dts/socfpga_cyclone5.dtsi

@@ -28,7 +28,7 @@
 			};
 		};
 
-		dwmmc0@ff704000 {
+		mmc0: dwmmc0@ff704000 {
 			num-slots = <1>;
 			broken-cd;
 			bus-width = <4>;

arch/arm/boot/dts/socfpga_cyclone5_socdk.dts

@@ -68,6 +68,10 @@
 	};
 };
 
+&mmc0 {
+	cd-gpios = <&gpio1 18 0>;
+};
+
 &usb1 {
 	status = "okay";
 };