Merge branch 'netdev_sysfs_symlink_rename'

Veaceslav Falico says:

====================
net: rename device's sysfs symlinks on name change

First patch only adds helper functions and cleans up the code a bit, second
one already does the renaming.

v1->v2:
Don't export the function, as it's used only in dev.c.
====================

Reported-by: Ding Tianhong <dingtianhong@huawei.com>
CC: Ding Tianhong <dingtianhong@huawei.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: Eric Dumazet <edumazet@google.com>
CC: Nicolas Dichtel <nicolas.dichtel@6wind.com>
CC: Cong Wang <amwang@redhat.com>
CC: netdev@vger.kernel.org
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>