ARM: dts: imx7d-sdb: add eMMC5.0 support

imx7d-sdb board has a eMMC5.0 on usdhc3. This eMMC support HS400.
This patch add usdhc3 support for HS400
Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
Acked-by: Dong Aisheng <aisheng.dong@freescale.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d-sdb.dts

@@ -241,6 +241,19 @@ &usdhc1 {
 	status = "okay";
 };
 
+&usdhc3 {
+	pinctrl-names = "default", "state_100mhz", "state_200mhz";
+	pinctrl-0 = <&pinctrl_usdhc3>;
+	pinctrl-1 = <&pinctrl_usdhc3_100mhz>;
+	pinctrl-2 = <&pinctrl_usdhc3_200mhz>;
+	assigned-clocks = <&clks IMX7D_USDHC3_ROOT_CLK>;
+	assigned-clock-rates = <400000000>;
+	bus-width = <8>;
+	fsl,tuning-step = <2>;
+	non-removable;
+	status = "okay";
+};
+
 &iomuxc {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_hog>;