spi: sh-msiof: Document R-Car M3-N support

Document support for the MSIOF module in the Renesas M3-N (r8a77965) SoC.

No driver update is needed.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

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

@@ -10,6 +10,7 @@ Required properties:
 			 "renesas,msiof-r8a7794" (R-Car E2)
 			 "renesas,msiof-r8a7795" (R-Car H3)
 			 "renesas,msiof-r8a7796" (R-Car M3-W)
+			 "renesas,msiof-r8a77965" (R-Car M3-N)
 			 "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)