i.MX6UL: icore: Add SPL_OF_CONTROL support

Add OF_CONTROL support for SPL code.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/arch/arm/dts/imx6ul-isiot-emmc.dts b/arch/arm/dts/imx6ul-isiot-emmc.dts
index 677de96..a611e3b 100644
--- a/arch/arm/dts/imx6ul-isiot-emmc.dts
+++ b/arch/arm/dts/imx6ul-isiot-emmc.dts
@@ -50,6 +50,7 @@
 };
 
 &usdhc2 {
+	u-boot,dm-spl;
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_usdhc2>;
 	cd-gpios = <&gpio4 5 GPIO_ACTIVE_LOW>;
@@ -60,6 +61,7 @@
 
 &iomuxc {
 	pinctrl_usdhc2: usdhc2grp {
+		u-boot,dm-spl;
 		fsl,pins = <
 			MX6UL_PAD_NAND_RE_B__USDHC2_CLK      0x17070
 			MX6UL_PAD_NAND_WE_B__USDHC2_CMD      0x10070