Merge branch 'tcp_fast_open_synack_fin'

Eric Dumazet says:

====================
tcp: fastopen: accept data/FIN present in SYNACK

Implements RFC 7413 (TCP Fast Open) 4.2.2, accepting payload and/or FIN
in SYNACK messages, and prepare removal of SYN flag in tcp_recvmsg()
====================

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