ARM: zynq: DT: Fix Ethernet phy modes

The used PHYs should be qualified as 'rgmii-id' instead of just 'rgmii'.
For the Zed board this seems to make a difference between working and
broken Ethernet.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>

arch/arm/boot/dts/zynq-zc702.dts

@@ -44,7 +44,7 @@ &can0 {
 
 &gem0 {
 	status = "okay";
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 };
 
 &i2c0 {

arch/arm/boot/dts/zynq-zc706.dts

@@ -32,7 +32,7 @@ chosen {
 
 &gem0 {
 	status = "okay";
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 };
 
 &i2c0 {

arch/arm/boot/dts/zynq-zed.dts

@@ -32,7 +32,7 @@ chosen {
 
 &gem0 {
 	status = "okay";
-	phy-mode = "rgmii";
+	phy-mode = "rgmii-id";
 };
 
 &sdhci0 {