net: core: Add a GID field to struct sock.

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I7LTRR
CVE: NA

Reference: https://gitee.com/openeuler/kernel/commit/f6740a11189620e5fd5ec0642c41b00f71b01689



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UID and GID are requested as filters for socketmap, but we can only get
UID from sock structure. This patch adds GID field to struct sock as UID.

Signed-off-by: Lu Wei <luwei32@huawei.com>
Signed-off-by: Liu Jian <liujian56@huawei.com>
Conflicts:
	include/net/sock.h
	net/core/sock.c
Signed-off-by: JofDiamonds <kwb0523@163.com>
Reviewed-by: wuchangye <wuchangye@huawei.com>