The original implementation incorrectly uses netdev->dev_addrs.

Use netdev->uc instead.  Also use netdev_for_each_uc_addr to iterate
over the addresses.  Fix comment.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>