uapi/linux/prctl: provide macro definitions for the PR_SCHED_CORE type argument

mainline inclusion
from mainline-v5.16-rc1
commit 61bc346c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5OOWG
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=61bc346ce64a3864ac55f5d18bdc1572cda4fb18

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Commit 7ac592aa ("sched: prctl() core-scheduling interface")
made use of enum pid_type in prctl's arg4; this type and the associated
enumeration definitions are not exposed to userspace.  Christian
has suggested to provide additional macro definitions that convey
the meaning of the type argument more in alignment with its actual
usage, and this patch does exactly that.

Link: https://lore.kernel.org/r/20210825170613.GA3884@asgard.redhat.com


Suggested-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Complements: 7ac592aa ("sched: prctl() core-scheduling interface")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Lin Shengwang <linshengwang1@huawei.com>
Reviewed-by: lihua <hucool.lihua@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>