Current hwmode settings are "vepa" or "veb". These are for NIC interfaces
with basic bridging function offloaded to HW. Add new "swdev" for full
switch device offloads.
Signed-off-by: Scott Feldman <sfeldma@gmail.com> Signed-off-by: Jiri Pirko <jiri@resnulli.us> Signed-off-by: David S. Miller <davem@davemloft.net>