COPYING: add explicit license file
COPYING: add explicit license file

Signed-off-by: Eric Nelson <3613bade79ee1cd4cc74802f4c7c26501a46456e@boundarydevices.com>

pacificIT/imx_usb_loader,bwalle/imx_usb_loader,vstehle/imx_usb_loader,Adellica/imx_usb_loader,boundarydevices/imx_usb_loader,lucaceresoli/imx_usb_loader