Add DFU Suffix for ARM boards (#5763)

Add DFU Suffix for ARM boards (#5763)

* Add DFU Suffix for ARM boards

* Blindly flash DFU SUFFIX ARGS for now

* Fix commented out check

* Fix DFU Suffix Argument check

Thank you jack!

* Update Travis CI Scripts to include dfu-util

So we can get dfu-suffix as well

* Manually add dfu-suffix package

* Use external repo for newer version of dfu-util

One that includes dfu-suffix

* Update .travis.yml

* Silence unnecessary output from dfu-suffix