net: send SYNACK packet with accepted fwmark

stable inclusion
from stable-5.10.53
commit b61d8814c4779f7810c96fa1d1d9e68fbd9d91df
bugzilla: 175574 https://gitee.com/openeuler/kernel/issues/I4DTUX

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b61d8814c4779f7810c96fa1d1d9e68fbd9d91df



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commit 43b90bfa upstream.

commit e05a90ec ("net: reflect mark on tcp syn ack packets")
fixed IPv4 only.

This part is for the IPv6 side.

Fixes: e05a90ec ("net: reflect mark on tcp syn ack packets")
Signed-off-by: Alexander Ovechkin <ovov@yandex-team.ru>
Acked-by: Dmitry Yakunin <zeil@yandex-team.ru>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>