arm64: dts: allwinner: h6: enable USB2 on Pine H64

Pine H64 board has both the USB2 OTG pins and the USB2 host pins on H6
SoC wired out to USB Type-A ports.

Enable them.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Reviewed-by: Chen-Yu Tsai <wens@csie.org>
Tested-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Chen-Yu Tsai <wens@csie.org>