dt-bindings: sifive-l2-cache: Fix 'select' matching

When the schema fixups are applied to 'select' the result is a single
entry is required for a match, but that will never match as there should
be 2 entries. Also, a 'select' schema should have the widest possible
match, so use 'contains' which matches the compatible string(s) in any
position and not just the first position.

Fixes: 993dcfac64eb ("dt-bindings: riscv: sifive-l2-cache: convert bindings to json-schema")
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

Documentation/devicetree/bindings/riscv/sifive-l2-cache.yaml

@@ -24,10 +24,10 @@ allOf:
 select:
   properties:
     compatible:
-      items:
-        - enum:
-            - sifive,fu540-c000-ccache
-            - sifive,fu740-c000-ccache
+      contains:
+        enum:
+          - sifive,fu540-c000-ccache
+          - sifive,fu740-c000-ccache
 
   required:
     - compatible