arm64: dts: allwinner: h6: add USB2-related device nodes

Allwinner H6 has two USB2 ports, one OTG and one host-only.

Add device tree nodes related to 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>