arm64: allwinner: h6: add R_INTC interrupt controller

Allwinner H6 SoC has also a R_INTC interrupt controller like Allwinner
A64 SoC, but has its base address changed due to the memory map change
in H6.

Add it into the device tree.

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