dccp: Call inet6_destroy_sock() via sk->sk_destruct().

mainline inclusion
from mainline-v6.2-rc1
commit 1651951e
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I6TPN9
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?h=v6.3-rc2&id=1651951ebea54970e0bda60c638fc2eee7a6218f



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

After commit d38afeec ("tcp/udp: Call inet6_destroy_sock()
in IPv6 sk->sk_destruct()."), we call inet6_destroy_sock() in
sk->sk_destruct() by setting inet6_sock_destruct() to it to make
sure we do not leak inet6-specific resources.

DCCP sets its own sk->sk_destruct() in the dccp_init_sock(), and
DCCPv6 socket shares it by calling the same init function via
dccp_v6_init_sock().

To call inet6_sock_destruct() from DCCPv6 sk->sk_destruct(), we
export it and set dccp_v6_sk_destruct() in the init function.

Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ziyang Xuan <william.xuanziyang@huawei.com>
Reviewed-by: Liu Jian <liujian56@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>