bnx2/bnx2-mips-09-5.0.0.j15.fw and cxgb3/t3fw-7.10.0.bin were
added by the respective maintainers, so assume the same licence
as for other versions of the firmware.
mts_mt9234mu.fw and mts_mt9234zba.fw were added by a user,
apparently with permission from the vendor but without any licence
specified, so treat them as unknown for now.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>