Merge branch 'inet-const'

Eric Dumazet says:

====================
inet: better const qualifier awareness

inet_sk() can be changed to propagate const qualifier,
thanks to container_of_const()

Following patches in this series add more const qualifiers.

Other helpers like tcp_sk(), udp_sk(), raw_sk(), ... will be handled
in following series.
====================

Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>