ARM: dts: dra7x: Make pinctrl and IOdelays for MMC2 available in SPL

The SPL can't use high speed MMC modes if the associated pinctrl and
IOdelays are described in the DTS.
Make them available in SPL by tagging the nodes with 'u-boot,dm-spl;'

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>
diff --git a/arch/arm/dts/dra76-evm-u-boot.dtsi b/arch/arm/dts/dra76-evm-u-boot.dtsi
index b007f78..a5a0694 100644
--- a/arch/arm/dts/dra76-evm-u-boot.dtsi
+++ b/arch/arm/dts/dra76-evm-u-boot.dtsi
@@ -13,3 +13,15 @@
 &cpsw_emac1 {
 	phy-handle = <&dp83867_1>;
 };
+
+&mmc2_pins_default {
+	u-boot,dm-spl;
+};
+
+&mmc2_pins_hs200 {
+	u-boot,dm-spl;
+};
+
+&mmc2_iodelay_hs200_conf {
+	u-boot,dm-spl;
+};