ipv6: Fix data races around sk->sk_prot.

mainline inclusion
from mainline-6.1-rc1
commit 364f997b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5W7YP
CVE: CVE-2022-3567

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=364f997b5cfe1db0d63a390fe7c801fa2b3115f6



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Commit 086d4905 ("ipv6: annotate some data-races around sk->sk_prot")
fixed some data-races around sk->sk_prot but it was not enough.

Some functions in inet6_(stream|dgram)_ops still access sk->sk_prot
without lock_sock() or rtnl_lock(), so they need READ_ONCE() to avoid
load tearing.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Liu Jian <liujian56@huawei.com>

Conflicts:
	net/ipv6/ipv6_sockglue.c
Reviewed-by: Yue Haibing <yuehaibing@huawei.com>
Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>