tcp: tcp_enter_quickack_mode() should be static

stable inclusion
from stable-v4.19.295
commit 0f9ca28a3ab5bc354b8c29e0d4765de42883dcd6
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I8EK5K


CVE: NA

--------------------------------

[ Upstream commit 03b123de ]

After commit d2ccd7bc ("tcp: avoid resetting ACK timer in DCTCP"),
tcp_enter_quickack_mode() is only used from net/ipv4/tcp_input.c.

Fixes: d2ccd7bc ("tcp: avoid resetting ACK timer in DCTCP")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Yuchung Cheng <ycheng@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Link: https://lore.kernel.org/r/20230718162049.1444938-1-edumazet@google.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com>