ipv6: drop useless rcu_read_lock() in anycast

These code is now protected by rtnl lock, rcu read lock
is useless now.

Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/linux/netdevice.h
Simple merge

diff --cc net/core/dev.c
Simple merge

diff --cc net/ipv6/anycast.c
Simple merge