dt-bindings: display/ti: Simplify dma-coherent property

Common boolean properties need to be only allowed in the binding
(":true"), because their type is already defined by core DT schema.
Simplify dma-coherent property to match common syntax.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Link: https://patch.msgid.link/20251115122120.35315-4-krzk@kernel.org
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>

Author: krzk

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

@@ -84,8 +84,7 @@ properties:
     maxItems: 1
     description: phandle to the associated power domain
 
-  dma-coherent:
-    type: boolean
+  dma-coherent: true
 
   ports:
     $ref: /schemas/graph.yaml#/properties/ports

Documentation/devicetree/bindings/display/ti/ti,j721e-dss.yaml

@@ -103,8 +103,7 @@ properties:
     maxItems: 1
     description: phandle to the associated power domain
 
-  dma-coherent:
-    type: boolean
+  dma-coherent: true
 
   ports:
     $ref: /schemas/graph.yaml#/properties/ports