arm64: dts: enable otg mode for dwc3 usb ip on layerscape

layerscape otg function should be supported HNP SRP and ADP protocol
accroing to rm doc, but dwc3 code not realize it and use id pin to
detect who is host or device(0 is host 1 is device) this patch is to
enable OTG mode on ls1028ardb ls1088ardb and ls1046ardb in dts
Signed-off-by: Yinbo Zhu <yinbo.zhu@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/fsl-ls1028a-rdb.dts

@@ -184,3 +184,7 @@ &sai4 {
 &sata {
 	status = "okay";
 };
+
+&usb1 {
+	dr_mode = "otg";
+};

arch/arm64/boot/dts/freescale/fsl-ls1046a-rdb.dts

@@ -122,6 +122,10 @@ qflash1: flash@1 {
 	};
 };
 
+&usb1 {
+	dr_mode = "otg";
+};
+
 #include "fsl-ls1046-post.dtsi"
 
 &fman0 {

arch/arm64/boot/dts/freescale/fsl-ls1088a-rdb.dts

@@ -95,5 +95,6 @@ &usb0 {
 };
 
 &usb1 {
+	dr_mode = "otg";
 	status = "okay";
 };