of: Add vendor prefix for Pervasive Displays

Pervasive Displays Inc. designs, develops, and manufactures low-power
electrophoretic (e-ink) display modules and supporting electronics for
commercial and industrial display applications.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NNoralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1496934875-51984-2-git-send-email-noralf@tronnes.org

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -241,6 +241,7 @@ oxsemi	Oxford Semiconductor, Ltd.
 panasonic	Panasonic Corporation
 parade	Parade Technologies Inc.
 pericom	Pericom Technology Inc.
+pervasive	Pervasive Displays, Inc.
 phytec	PHYTEC Messtechnik GmbH
 picochip	Picochip Ltd
 pine64	Pine64