Merge branch 'eth_hw_addr_gen-for-switches'

Jakub Kicinski says:

====================
ethernet: add eth_hw_addr_gen() for switches

While doing the last polishing of the drivers/ethernet
changes I realized we have a handful of drivers offsetting
some base MAC addr by an id. So I decided to add a helper
for it. The helper takes care of wrapping which is probably
not 100% necessary but seems like a good idea. And it saves
driver side LoC (the diffstat is actually negative if we
compare against the changes I'd have to make if I was to
convert all these drivers to not operate directly on
netdev->dev_addr).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>