arm64: dts: allwinner: a64: add R_I2C controller

arm64: dts: allwinner: a64: add R_I2C controller

Allwinner A64 has a I2C controller, which is in the R_ MMIO zone and has
two groups of pinmuxes on PL bank, so it's called R_I2C.

Add support for this I2C controller and the pinmux which doesn't conflict
with RSB.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Gbp-Pq: Topic features/arm64/pinebook
Gbp-Pq: Name 0002-arm64-dts-allwinner-a64-add-R_I2C-controller.patch