[NETNS][IPV6] udp - make proc handle the network namespace

This patch makes the common udp proc functions to take care of which
socket they should show taking into account the namespace it belongs.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

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