arm64: Add Renesas R8A774A1 support

Add configuration option for the RZ/G2M (R8A774A1) SoC.
Signed-off-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Chris Paterson <chris.paterson2@renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

arch/arm64/Kconfig.platforms

@@ -164,6 +164,12 @@ config ARCH_RENESAS
 	help
 	  This enables support for the ARMv8 based Renesas SoCs.
 
+config ARCH_R8A774A1
+	bool "Renesas RZ/G2M SoC Platform"
+	depends on ARCH_RENESAS
+	help
+	  This enables support for the Renesas RZ/G2M SoC.
+
 config ARCH_R8A7795
 	bool "Renesas R-Car H3 SoC Platform"
 	depends on ARCH_RENESAS