Merge branch 'bug fixes for sockmap'

Xu Kuohai says:

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bug fixes and a new test case for sockmap.

v3:
fix bpf ci failure

v2: https://lore.kernel.org/bpf/20230803064838.108784-1-xukuohai@huaweicloud.com
add a test case

v1:
https://lore.kernel.org/bpf/20230728105649.3978774-1-xukuohai@huaweicloud.com
https://lore.kernel.org/bpf/20230728105717.3978849-1-xukuohai@huaweicloud.com


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Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>