dt-bindings: Add vendor prefix for Dell Inc.

Dell makes computers and perhaps other stuff. Their web site is
http://www.dell.com/.
Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Signed-off-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -233,6 +233,8 @@ patternProperties:
     description: DataImage, Inc.
   "^davicom,.*":
     description: DAVICOM Semiconductor, Inc.
+  "^dell,.*":
+    description: Dell Inc.
   "^delta,.*":
     description: Delta Electronics, Inc.
   "^denx,.*":