soc: renesas: Identify R-Car H3e-2G and M3e-2G

Add support for identifying the R-Car H3e-2G (R8A779M1) and R-Car M3e-2G
(R8A779M3) SoCs.

As these are different gradings of the already supported R-Car H3 ES3.0
(R8A77951) and M3-W+ (R8A77961) SoCs, support for them is enabled
through the existing ARCH_R8A77951 and ARCH_R8A77961 configuration
symbols.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://lore.kernel.org/r/42b4578ab4739cb48ec3aed0a447fc40c34de1e5.1626708063.git.geert+renesas@glider.be