ARM: shmobile: Document RZ/G1N SoC DT binding

Document the RZ/G1N (r8a7744) SoC.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>

Documentation/devicetree/bindings/arm/shmobile.txt

@@ -17,6 +17,8 @@ SoCs:
     compatible = "renesas,r8a7742"
   - RZ/G1M (R8A77430)
     compatible = "renesas,r8a7743"
+  - RZ/G1N (R8A77440)
+    compatible = "renesas,r8a7744"
   - RZ/G1E (R8A77450)
     compatible = "renesas,r8a7745"
   - R-Car M1A (R8A77781)