arm64: dts: renesas: Add Renesas R8A779M0 SoC support

Add support for the Renesas R-Car H3e (R8A779M0) SoC, which is a
different grading of the R-Car H3 ES3.0 (R8A77951) SoC.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/a82a72bec176fd5bdd71c392aa325eb0917ee81a.1628766192.git.geert+renesas@glider.be