dt-bindings: net: tsnep: Allow dma-coherent

Within SoCs like ZynqMP, FPGA logic can be connected to different kinds
of AXI master ports. Also cache coherent AXI master ports are available.
The property "dma-coherent" is used to signal that DMA is cache
coherent.

Add "dma-coherent" property to allow the configuration of cache coherent
DMA.
Signed-off-by: Gerhard Engleder <gerhard@engleder-embedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/engleder,tsnep.yaml

@@ -22,6 +22,8 @@ properties:
   interrupts:
     maxItems: 1
 
+  dma-coherent: true
+
   local-mac-address: true
 
   mac-address: true