dt-bindings: riscv: add Zcmop ISA extension description

Add description for the Zcmop (Compressed May-Be-Operations) ISA
extension which was ratified in commit c732a4f39a4c ("Zcmop is
ratified/1.0") of the riscv-isa-manual.

Signed-off-by: Clément Léger <cleger@rivosinc.com>
Acked-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20240619113529.676940-13-cleger@rivosinc.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

Documentation/devicetree/bindings/riscv/extensions.yaml

@@ -252,6 +252,11 @@ properties:
             merged in the riscv-isa-manual by commit dbc79cf28a2 ("Initial seed
             of zc.adoc to src tree.").
 
+        - const: zcmop
+          description:
+            The standard Zcmop extension version 1.0, as ratified in commit
+            c732a4f39a4 ("Zcmop is ratified/1.0") of the riscv-isa-manual.
+
         - const: zfa
           description:
             The standard Zfa extension for additional floating point
@@ -579,6 +584,13 @@ properties:
                 const: zca
             - contains:
                 const: f
+      # Zcmop depends on Zca
+      - if:
+          contains:
+            const: zcmop
+        then:
+          contains:
+            const: zca
 
 allOf:
   # Zcf extension does not exist on rv64