dt-bindings: dvfs: drop unneeded quotes

Cleanup bindings dropping unneeded quotes. Once all these are fixed,
checking for this can be enabled in yamllint.
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230609140742.65018-1-krzysztof.kozlowski@linaro.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/dvfs/performance-domain.yaml

@@ -42,7 +42,7 @@ properties:
     enum: [ 0, 1 ]
 
   performance-domains:
-    $ref: '/schemas/types.yaml#/definitions/phandle-array'
+    $ref: /schemas/types.yaml#/definitions/phandle-array
     description:
       A phandle and performance domain specifier as defined by bindings of the
       performance controller/provider specified by phandle.