dt-bindings: clock: baikal,bt1-ccu-div: add top-level constraints

Properties with variable number of items per each device are expected to
have widest constraints in top-level "properties:" block and further
customized (narrowed) in "if:then:". Add missing top-level constraints
for clocks and clock-names.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Serge Semin <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

Documentation/devicetree/bindings/clock/baikal,bt1-ccu-div.yaml

···
   "#reset-cells":
     const: 1
 
-  clocks: true
+  clocks:
+    minItems: 3
+    maxItems: 4
 
-  clock-names: true
+  clock-names:
+    minItems: 3
+    maxItems: 4
 
 additionalProperties: false