dt-bindings: arm: renesas: Document iWave RZ/G1N SOM

Document the iW-RainboW-G20M-RZ/G1N Qseven device tree bindings,
listing it as a supported system on module.
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>

Documentation/devicetree/bindings/arm/shmobile.txt

@@ -101,6 +101,8 @@ Boards:
     compatible = "iwave,g20d", "iwave,g20m", "renesas,r8a7743"
   - iWave Systems RZ/G1M Qseven System On Module (iW-RainboW-G20M-Qseven)
     compatible = "iwave,g20m", "renesas,r8a7743"
+  - iWave Systems RZ/G1N Qseven System On Module (iW-RainboW-G20M-Qseven)
+    compatible = "iwave,g20m", "renesas,r8a7744"
   - Kingfisher (SBEV-RCAR-KF-M03)
     compatible = "shimafuji,kingfisher"
   - Koelsch (RTP0RC7791SEB00010S)