Merge branch 'net-enable-udp-v6-sockets-receiving-v4-packets-with-udp'

Xin Long says:

====================
net: enable udp v6 sockets receiving v4 packets with UDP

Currently, udp v6 socket can not process v4 packets with UDP GRO, as
udp_encap_needed_key is not increased when udp_tunnel_encap_enable()
is called for v6 socket.

This patchset is to increase it and remove the unnecessary code in
bareudp in Patch 1/2, and improve rxrpc encap_enable by calling
udp_tunnel_encap_enable().
====================

Link: https://lore.kernel.org/r/cover.1612342376.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>