bna: fix list corruption

Use list_move_tail() to move MAC address entry from list of pending
to list of active entries. Simple list_add_tail() leaves the entry
also in the first list, this leads to list corruption.

Cc: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Rasesh Mody <rasesh.mody@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>