dt-bindings: Add vendor prefix for MeLE

MeLE is a Chinese manufacturer of TV boxes and Mini PCs.

Cc: [e-mail]
Acked-by: Rob Herring <[e-mail]>
Signed-off-by: Andreas Färber <[e-mail]>

Documentation/devicetree/bindings/vendor-prefixes.txt

···
 meas	Measurement Specialties
 mediatek	MediaTek Inc.
 megachips	MegaChips
+mele	Shenzhen MeLE Digital Technology Ltd.
 melexis	Melexis N.V.
 melfas	MELFAS Inc.
 mellanox	Mellanox Technologies