dt-bindings: i2c: renesas,rcar-i2c: Add r8a779h0 support

Document support for the I2C Bus Interfaces in the Renesas R-Car V4M
(R8A779H0) SoC.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>