inet: make no_pmtu_disc per namespace and kill ipv4_config

The other field in ipv4_config, log_martians, was converted to a
per-interface setting, so we can just remove the whole structure.

Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/net/ip.h
Simple merge

diff --cc include/net/netns/ipv4.h
Simple merge

diff --cc net/ipv4/af_inet.c
Simple merge

diff --cc net/ipv4/icmp.c
Simple merge

diff --cc net/ipv4/sysctl_net_ipv4.c
Simple merge

diff --cc net/ipv4/xfrm4_state.c
Simple merge

diff --cc net/ipv6/af_inet6.c
Simple merge