dt-bindings: display: renesas,rzg2l-du: Add RZ/T2H and RZ/N2H support

Document the Display Unit (DU) support for the RZ/T2H and RZ/N2H SoCs.

The DU block on RZ/T2H is functionally equivalent to the RZ/G2UL DU and
supports the DPI interface, but includes SoC-specific register differences
and has no reset control. Add a dedicated compatible string to represent
this variant and update the allOf constraints accordingly.

As the DU implementation on RZ/N2H matches RZ/T2H, describe it using an
RZ/N2H specific compatible string with the RZ/T2H compatible as fallback.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Link: https://patch.msgid.link/20260519160825.4082566-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>

Documentation/devicetree/bindings/display/renesas,rzg2l-du.yaml

@@ -21,6 +21,7 @@ properties:
           - renesas,r9a07g043u-du # RZ/G2UL
           - renesas,r9a07g044-du # RZ/G2{L,LC}
           - renesas,r9a09g057-du # RZ/V2H(P)
+          - renesas,r9a09g077-du # RZ/T2H
       - items:
           - enum:
               - renesas,r9a07g054-du    # RZ/V2L
@@ -28,6 +29,9 @@ properties:
       - items:
           - const: renesas,r9a09g056-du # RZ/V2N
           - const: renesas,r9a09g057-du # RZ/V2H(P) fallback
+      - items:
+          - const: renesas,r9a09g087-du # RZ/N2H
+          - const: renesas,r9a09g077-du # RZ/T2H fallback
 
   reg:
     maxItems: 1
@@ -83,7 +87,6 @@ required:
   - interrupts
   - clocks
   - clock-names
-  - resets
   - power-domains
   - ports
   - renesas,vsps
@@ -95,7 +98,9 @@ allOf:
       properties:
         compatible:
           contains:
-            const: renesas,r9a07g043u-du
+            enum:
+              - renesas,r9a07g043u-du
+              - renesas,r9a09g077-du
     then:
       properties:
         ports:
@@ -138,6 +143,17 @@ allOf:
 
           required:
             - port@0
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: renesas,r9a09g077-du
+    then:
+      properties:
+        resets: false
+    else:
+      required:
+        - resets
 
 examples:
   # RZ/G2L DU