phy: rcar-gen3-usb2: revise the example of device tree doc

The clocks property should be set to &cpg, not &mstpX_clks.
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt

@@ -30,11 +30,11 @@ Example (R-Car H3):
 		compatible = "renesas,usb2-phy-r8a7795", "renesas,rcar-gen3-usb2-phy";
 		reg = <0 0xee080200 0 0x700>;
 		interrupts = <GIC_SPI 108 IRQ_TYPE_LEVEL_HIGH>;
-		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>;
+		clocks = <&cpg CPG_MOD 703>;
 	};
 
 	usb-phy@ee0a0200 {
 		compatible = "renesas,usb2-phy-r8a7795", "renesas,rcar-gen3-usb2-phy";
 		reg = <0 0xee0a0200 0 0x700>;
-		clocks = <&mstp7_clks R8A7795_CLK_EHCI0>;
+		clocks = <&cpg CPG_MOD 702>;
 	};