rockchip: dts: rk3328-rock64: enable usb3 xhci controller

Rock64 has a USB3.0 port, enable the controller so that we can use it.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

arch/arm/dts/rk3328-rock64-u-boot.dtsi

@@ -32,3 +32,7 @@
 &sdmmc {
 	u-boot,dm-pre-reloc;
 };
+
+&usb_host0_xhci {
+	status = "okay";
+};