dt-bindings: mfd: ti,j721e-system-controller: Fix incorrect pattern property

Pattern properties go under 'patternProperties', not 'properties'.
Otherwise, the pattern is treated as a literal string.

A corresponding meta-schema check has been added to catch bad DT property
names like this.

Fixes: e0f94691 ("dt-bindings: mfd: ti,j721e-system-controller.yaml: Add J721e system controller")
Cc: Roger Quadros <rogerq@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Kishon Vijay Abraham I <kishon@ti.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Link: https://lore.kernel.org/r/20201002230606.3522954-1-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/mfd/ti,j721e-system-controller.yaml

@@ -38,8 +38,8 @@ properties:
 
   ranges: true
 
-# Optional children
-
+patternProperties:
+  # Optional children
   "^serdes-ln-ctrl@[0-9a-f]+$":
     type: object
     description: |