spi: sh-msiof: Add r8a774a1 support

Document RZ/G2M (R8A774A1) SoC bindings.
Signed-off-by: Fabrizio Castro <fabrizio.castro@bp.renesas.com>
Reviewed-by: Biju Das <biju.das@bp.renesas.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/sh-msiof.txt

@@ -3,6 +3,7 @@ Renesas MSIOF spi controller
 Required properties:
 - compatible           : "renesas,msiof-r8a7743" (RZ/G1M)
 			 "renesas,msiof-r8a7745" (RZ/G1E)
+			 "renesas,msiof-r8a774a1" (RZ/G2M)
 			 "renesas,msiof-r8a7790" (R-Car H2)
 			 "renesas,msiof-r8a7791" (R-Car M2-W)
 			 "renesas,msiof-r8a7792" (R-Car V2H)
@@ -14,7 +15,7 @@ Required properties:
 			 "renesas,msiof-sh73a0" (SH-Mobile AG5)
 			 "renesas,sh-mobile-msiof" (generic SH-Mobile compatibile device)
 			 "renesas,rcar-gen2-msiof" (generic R-Car Gen2 and RZ/G1 compatible device)
-			 "renesas,rcar-gen3-msiof" (generic R-Car Gen3 compatible device)
+			 "renesas,rcar-gen3-msiof" (generic R-Car Gen3 and RZ/G2 compatible device)
 			 "renesas,sh-msiof"      (deprecated)
 
 			 When compatible with the generic version, nodes