dt-bindings: riscv: cpus: 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>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230609140706.64623-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Documentation/devicetree/bindings/riscv/cpus.yaml

@@ -61,7 +61,7 @@ properties:
       hart.  These values originate from the RISC-V Privileged
       Specification document, available from
       https://riscv.org/specifications/
-    $ref: "/schemas/types.yaml#/definitions/string"
+    $ref: /schemas/types.yaml#/definitions/string
     enum:
       - riscv,sv32
       - riscv,sv39
@@ -95,7 +95,7 @@ properties:
       While the isa strings in ISA specification are case
       insensitive, letters in the riscv,isa string must be all
       lowercase.
-    $ref: "/schemas/types.yaml#/definitions/string"
+    $ref: /schemas/types.yaml#/definitions/string
     pattern: ^rv(?:64|32)imaf?d?q?c?b?k?j?p?v?h?(?:[hsxz](?:[a-z])+)?(?:_[hsxz](?:[a-z])+)*$
 
   # RISC-V requires 'timebase-frequency' in /cpus, so disallow it here
@@ -120,7 +120,7 @@ properties:
       - interrupt-controller
 
   cpu-idle-states:
-    $ref: '/schemas/types.yaml#/definitions/phandle-array'
+    $ref: /schemas/types.yaml#/definitions/phandle-array
     items:
       maxItems: 1
     description: |