dt-bindings: clock: renesas,cpg-clocks: 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-output-names.

Signed-off-by: Krzysztof Kozlowski <[e-mail]>
Acked-by: Conor Dooley <[e-mail]>
Reviewed-by: Geert Uytterhoeven <[e-mail]>
Link: https://lore.kernel.org/[e-mail]
Signed-off-by: Geert Uytterhoeven <[e-mail]>

Documentation/devicetree/bindings/clock/renesas,cpg-clocks.yaml

···
   reg:
     maxItems: 1
 
-  clocks: true
+  clocks:
+    minItems: 1
+    maxItems: 3
 
   '#clock-cells':
     const: 1
 
-  clock-output-names: true
+  clock-output-names:
+    minItems: 3
+    maxItems: 17
 
   renesas,mode:
     description: Board-specific settings of the MD_CK* bits on R-Mobile A1