arm64: dts: mediatek: mt8516: rename usb phy

The USB phy node is named usb0_phy but there is only one phy with
2 ports on MT8516. Rename the phy to make it more obvious it can
also support the usb1 node.
The usb1 node will be added in a follow-up commit.
Signed-off-by: Fabien Parent <fparent@baylibre.com>
Link: https://lore.kernel.org/r/20201014162404.1312544-1-fparent@baylibre.comSigned-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm64/boot/dts/mediatek/mt8516.dtsi

@@ -455,7 +455,7 @@ usb0: usb@11100000 {
 			status = "disabled";
 		};
 
-		usb0_phy: usb@11110000 {
+		usb_phy: usb@11110000 {
 			compatible = "mediatek,generic-tphy-v1";
 			reg = <0 0x11110000 0 0x800>;
 			#address-cells = <2>;

arch/arm64/boot/dts/mediatek/pumpkin-common.dtsi

@@ -195,7 +195,7 @@ usb_con: connector {
 	};
 };
 
-&usb0_phy {
+&usb_phy {
 	status = "okay";
 };