spi: dt-bindings: renesas,rspi: Document RZ/G2L SoC

Add RSPI binding documentation for Renesas RZ/G2L SoC.

RSPI block is identical to one found on RZ/A, so no driver changes are
required. The fallback compatible string "renesas,rspi-rz" will be used
on RZ/G2L.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211118031041.2312-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Documentation/devicetree/bindings/spi/renesas,rspi.yaml

@@ -21,7 +21,8 @@ properties:
           - enum:
               - renesas,rspi-r7s72100  # RZ/A1H
               - renesas,rspi-r7s9210   # RZ/A2
-          - const: renesas,rspi-rz     # RZ/A
+              - renesas,r9a07g044-rspi # RZ/G2{L,LC}
+          - const: renesas,rspi-rz     # RZ/A and RZ/G2{L,LC}
 
       - items:
           - enum:
@@ -122,6 +123,7 @@ allOf:
           contains:
             enum:
               - renesas,qspi
+              - renesas,r9a07g044-rspi
     then:
       required:
         - resets