arm64: allwinner: h5: enable USB OTG on Orange Pi PC 2 board

Orange Pi PC 2 board features a OTG port like the one on older H3 Orange
Pi's, with PG12 pin being the id det pin and PL2 being the vbus driver
pin.

Add support for it.

Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>