dt-bindings: display: bridge: ldb: Add check for reg and reg-names

Make "reg" property mandatory for all LDB devices and "reg-names"
mandatory for i.MX8MP and i.MX93 which have two "reg" values. The
i.MX6SX has only one "reg" value so the "reg-names" property there
is optional and not needed.

Signed-off-by: Marek Vasut <marek.vasut@mailbox.org>
Link: https://patch.msgid.link/20260106012236.295834-1-marek.vasut@mailbox.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Documentation/devicetree/bindings/display/bridge/fsl,ldb.yaml

@@ -59,6 +59,7 @@ required:
   - compatible
   - clocks
   - ports
+  - reg
 
 allOf:
   - if:
@@ -73,6 +74,15 @@ allOf:
         ports:
           properties:
             port@2: false
+  - if:
+      not:
+        properties:
+          compatible:
+            contains:
+              const: fsl,imx6sx-ldb
+    then:
+      required:
+        - reg-names
 
 additionalProperties: false