dt-bindings: mailbox: amlogic,meson-gxbb-mhu: Add missing interrupts maxItems

Lists should have fixed constraint, so add missing maxItems to the
"interrupts" property.  Since minItems=maxItems, the minItems is implied
by dtschema so can be dropped.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Jassi Brar <jassisinghbrar@gmail.com>

Author: krzk

Documentation/devicetree/bindings/mailbox/amlogic,meson-gxbb-mhu.yaml

@@ -27,7 +27,7 @@ properties:
     maxItems: 1
 
   interrupts:
-    minItems: 3
+    maxItems: 3
     description:
       Contains the interrupt information corresponding to each of the 3 links
       of MHU.