devicetree: add Garmin vendor prefix

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Matt Ranostay <matt@ranostay.consulting>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Documentation/devicetree/bindings/vendor-prefixes.txt

@@ -104,6 +104,7 @@ firefly	Firefly
 focaltech	FocalTech Systems Co.,Ltd
 friendlyarm	Guangzhou FriendlyARM Computer Tech Co., Ltd
 fsl	Freescale Semiconductor
+grmn	Garmin Limited
 ge	General Electric Company
 geekbuying	GeekBuying
 gef	GE Fanuc Intelligent Platforms Embedded Systems, Inc.