mainline inclusion
from mainline-5.14-rc1
commit c571bd75
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c571bd752e91602f092823b2f1ee685a74d2726c

-------------------------------------------------

Similar to prog_load make btf_load command to be availble to
bpf_prog_type_syscall program.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210514003623.28033-7-alexei.starovoitov@gmail.com
(cherry picked from commit c571bd75)
Signed-off-by: NWang Yufen <wangyufen@huawei.com>