Merge branch 'gtp-fixes'

Andreas Schultz says:

====================
various gtp fixes

I'm sorry for the compile error mess up in the last version.
It's no excuse for not test compiling, but the hunks got lost in
a rebase.

This is the part of the previous "simple gtp improvements" series
that Pablo indicated should go into net.

The addition of the module alias fixes genl family autoloading,
clearing the DF bit fixes a protocol violation in regard to the
specification and the netns comparison fixes a corner case of
cross netns recv.

v2->v3: fix compiler error introduced in rebase
====================

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