dm: dts: Convert driver model tags to use new schema

Now that Linux has accepted these tags, move the device tree files in
U-Boot over to use them.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/dts/am437x-sk-evm-u-boot.dtsi b/arch/arm/dts/am437x-sk-evm-u-boot.dtsi
index 3aa9195..43e519c 100644
--- a/arch/arm/dts/am437x-sk-evm-u-boot.dtsi
+++ b/arch/arm/dts/am437x-sk-evm-u-boot.dtsi
@@ -7,18 +7,18 @@
 
 /{
 	ocp {
-		u-boot,dm-spl;
+		bootph-pre-ram;
 	};
 };
 
 &uart0 {
-	u-boot,dm-spl;
+	bootph-pre-ram;
 };
 
 &i2c0 {
-	u-boot,dm-spl;
+	bootph-pre-ram;
 };
 
 &mmc1 {
-	u-boot,dm-spl;
+	bootph-pre-ram;
 };