dt-bindings: ata: dwc-ahci: add PHY clocks

Add PHY transmit and receive clocks as described by the
DW SATA AHCI HW manual.
Suggested-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Documentation/devicetree/bindings/ata/snps,dwc-ahci-common.yaml

@@ -31,11 +31,11 @@ properties:
       PM-alive clock, RxOOB detection clock, embedded PHYs reference (Rx/Tx)
       clock, etc.
     minItems: 1
-    maxItems: 4
+    maxItems: 6
 
   clock-names:
     minItems: 1
-    maxItems: 4
+    maxItems: 6
     items:
       oneOf:
         - description: Application APB/AHB/AXI BIU clock
@@ -48,6 +48,10 @@ properties:
           const: pmalive
         - description: RxOOB detection clock
           const: rxoob
+        - description: PHY Transmit Clock
+          const: asic
+        - description: PHY Receive Clock
+          const: rbc
         - description: SATA Ports reference clock
           const: ref