net: addr_list: add exclusive dev_uc_add and dev_mc_add

This adds a dev_uc_add_excl() and dev_mc_add_excl() calls
similar to the original dev_{uc|mc}_add() except it sets
the global bit and returns -EEXIST for duplicat entires.

This is useful for drivers that support SR-IOV, macvlan
devices and any other devices that need to manage the
unicast and multicast lists.

v2: fix typo UNICAST should be MULTICAST in dev_mc_add_excl()

CC: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>