bpf: Allow bpf_get_netns_cookie in BPF_PROG_TYPE_SK_MSG

mainline inclusion
from mainline-v6.5-rc3
commit fab60e29
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7NL40
CVE: NA

Reference: https://github.com/torvalds/linux/commit/fab60e29fcc6d60396da20d63d45fd0d305ba4e4



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We'd like to be able to identify netns from sk_msg hooks
to accelerate local process communication form different netns.

Signed-off-by: Xu Liu <liuxu623@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210820071712.52852-2-liuxu623@gmail.com


Signed-off-by: JofDiamonds <kwb0523@163.com>
Reviewed-by: wuchangye <wuchangye@huawei.com>