dt-bindings: arm: Document R-Car M3-N SoC DT bindings

Add device tree bindings documentation for Renesas R-Car M3-N (r8a77965)
SoC.
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/arm/shmobile.txt

@@ -39,6 +39,8 @@ SoCs:
     compatible = "renesas,r8a7795"
   - R-Car M3-W (R8A77960)
     compatible = "renesas,r8a7796"
+  - R-Car M3-N (R8A77965)
+    compatible = "renesas,r8a77965"
   - R-Car V3M (R8A77970)
     compatible = "renesas,r8a77970"
   - R-Car V3H (R8A77980)