Merge branch 'netdev-name'

Cong Wang says:

====================
net: forbid net devices named "all" "default" or "config"

/proc/sys/net/ipv[46]/conf/<dev> could conflict with
/proc/sys/net/ipv[46]/conf/(all|default). And /proc/net/vlan/<dev>
could conflict with /proc/net/vlan/config. Besides kernel warnings,
undefined behavior such as duplicated proc files also appears, therefore
we should forbid these names.

v2: introduce a helper function, suggested by Florian
    fix error handling for ipv6_add_dev() in addrconf_init()
====================

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