ARM: dts: renesas: Add Renesas R8A779H0 V4M SoC support

Add initial support for the Renesas R8A779H0 (R-Car V4M) SoC.

The current version is imported and modified from:
https://lore.kernel.org/linux-renesas-soc/4107bc3d7c31932da29e671ddf4b1564ba38a84c.1706194617.git.geert+renesas@glider.be/


The modifications contain nodes from previous version
which are useful in U-Boot and not part of the Linux
kernel DT yet. The following nodes were added:
- pfc
- gpio0..gpio7
- i2c0..i2c3
- avb0..avb2
- mmc0

Signed-off-by: Hai Pham <hai.pham.ud@renesas.com>