dt-bindings: net: nfc: s3fwrn5: Add optional clock

On some systems, S3FWRN5 depends on having an external clock enabled
to function correctly. Allow declaring that clock in the device tree.
Signed-off-by: NStephan Gerhold <stephan@gerhold.net>
Reviewed-by: NKrzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/devicetree/bindings/net/nfc/samsung,s3fwrn5.yaml

@@ -27,6 +27,9 @@ properties:
   reg:
     maxItems: 1
 
+  clocks:
+    maxItems: 1
+
   wake-gpios:
     maxItems: 1
     description:
@@ -80,6 +83,8 @@ examples:
 
             en-gpios = <&gpf1 4 GPIO_ACTIVE_HIGH>;
             wake-gpios = <&gpj0 2 GPIO_ACTIVE_HIGH>;
+
+            clocks = <&rpmcc 20>;
         };
     };
   # UART example on Raspberry Pi