of: Add vendor prefix for Lattice Semiconductor

Lattice Semiconductor Corporation is a manufacturer of integrated
circuits and IP products, including low-power FPGAs, video connectivity
devices and millimeter wave wireless products.

Website: http://latticesemi.com



Signed-off-by: Joel Holdsworth <joel@airwebreathe.org.uk>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Alan Tull <atull@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>