Merge branch 'ip_tunnel-netlink-parms'

Liu Jian says:

====================
Add helper functions to parse netlink msg of ip_tunnel

v1->v2: Move the implementation of the helper function to ip_tunnel_core.c
v2->v3: Change EXPORT_SYMBOL to EXPORT_SYMBOL_GPL
====================

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