dt-bindings: riscv: cpus: add a ref the common cpu schema

To permit validation of RISC-V cpu nodes, "additionalProperties: true"
needs to be swapped for "unevaluatedProperties: false". To facilitate
this in a way that passes dt_binding_check, a reference to the cpu
schema is required.

Disallow the generic cache-op-block-size property that that drags in,
since the RISC-V CBO extensions do not require a common size, and have
individual properties.
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Link: https://lore.kernel.org/r/20230615-dubiously-parasail-79d34cefedce@spudSigned-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Documentation/devicetree/bindings/riscv/cpus.yaml

@@ -23,6 +23,9 @@ description: |
   two cores, each of which has two hyperthreads, could be described as
   having four harts.
 
+allOf:
+  - $ref: /schemas/cpu.yaml#
+
 properties:
   compatible:
     oneOf:
@@ -98,6 +101,9 @@ properties:
     $ref: "/schemas/types.yaml#/definitions/string"
     pattern: ^rv(?:64|32)imaf?d?q?c?b?k?j?p?v?h?(?:[hsxz](?:[a-z])+)?(?:_[hsxz](?:[a-z])+)*$
 
+  # RISC-V has multiple properties for cache op block sizes as the sizes
+  # differ between individual CBO extensions
+  cache-op-block-size: false
   # RISC-V requires 'timebase-frequency' in /cpus, so disallow it here
   timebase-frequency: false