devicetree: sort the Garmin vendor prefix properly.

The addition of Garmin put it in the incorrect place.  This fixes that
issue.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 9b27c270

 ("devicetree: add Garmin vendor prefix")
Cc: Rob Herring <robh@kernel.org>
Cc: Matt Ranostay <matt@ranostay.consulting>
Cc: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>