arm64: allwinner: h6: add node for R_PIO pin controller

Allwinner H6 SoC has a R_PIO pin controller which controls PL and PM
GPIO banks.

Add support for it.

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