dt-bindings: dma: xilinx: 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 <[email protected]>
Reviewed-by: Harini Katakam <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Vinod Koul <[email protected]>

Author: krzk

Documentation/devicetree/bindings/dma/xilinx/xlnx,zynqmp-dma-1.0.yaml

@@ -59,8 +59,7 @@ properties:
   power-domains:
     maxItems: 1
 
-  dma-coherent:
-    description: present if dma operations are coherent
+  dma-coherent: true
 
 required:
   - "#dma-cells"