netfilter: use nfnetlink_unicast()

mainline inclusion
from mainline-v5.14-rc1
commit e0241ae6
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I58CKN
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e0241ae6ac59ffa318255640c047f7c90457fbe5



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

Replace netlink_unicast() calls by nfnetlink_unicast() which already
deals with translating EAGAIN to ENOBUFS as the nfnetlink core expects.

nfnetlink_unicast() calls nlmsg_unicast() which returns zero in case of
success, otherwise the netlink core function netlink_rcv_skb() turns
err > 0 into an acknowlegment.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Xu Jia <xujia39@huawei.com>
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>