Upstream changed the way firmware files are described (was in info.json, now in WHENCE text file).
Let the ebuild use the script from upstream instead of wget-ting files manually.
Note: eventually this will be pushed to some release, then need to rethink the approach
(e. g. consider putting enumerating firmware files in the ebuild itself).
Signed-off-by: Sv. Lockal <lockalsash@gmail.com>