Merge branch 'tcp-ECN-quickack'

Eric Dumazet says:

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tcp: reduce quickack pressure for ECN

Small patch series changing TCP behavior vs quickack and ECN

First patch is a refactoring, adding parameter to tcp_incr_quickack()
and tcp_enter_quickack_mode() helpers.

Second patch implements the change, lowering number of ACK packets
sent after an ECN event.
====================

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