dt-bindings: display: ti: Add support for am62a7 dss

The DSS controller on TI's AM62A7 SoC is an update from that on TI's
AM625 SoC. Like the DSS in AM625, the DSS in this SoC has 2 video
pipelines, but unlike the former, the latter only has one output port on
VP2 to service DPI display sinks.

Add the new controller's compatible.

Signed-off-by: Aradhya Bhatia <a-bhatia1@ti.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://lore.kernel.org/r/20231108171619.978438-2-a-bhatia1@ti.com
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

Documentation/devicetree/bindings/display/ti/ti,am65x-dss.yaml

@@ -23,6 +23,7 @@ properties:
   compatible:
     enum:
       - ti,am625-dss
+      - ti,am62a7,dss
       - ti,am65x-dss
 
   reg:
@@ -87,6 +88,7 @@ properties:
           For AM65x DSS, the OLDI output port node from video port 1.
           For AM625 DSS, the internal DPI output port node from video
           port 1.
+          For AM62A7 DSS, the port is tied off inside the SoC.
 
       port@1:
         $ref: /schemas/graph.yaml#/properties/port
@@ -108,6 +110,18 @@ properties:
       Input memory (from main memory to dispc) bandwidth limit in
       bytes per second
 
+allOf:
+  - if:
+      properties:
+        compatible:
+          contains:
+            const: ti,am62a7-dss
+    then:
+      properties:
+        ports:
+          properties:
+            port@0: false
+
 required:
   - compatible
   - reg