arm64: allwinner: a64: add EHCI0/OHCI0 nodes to A64 DTSI

Allwinner A64 SoC features a pair of EHCI/OHCI controllers that can be
set to wire to USB0 port (the OTG-capable one), which can be used to
provide a better performance in host mode.

Add their device tree nodes.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>