Merge branch 'bpf-follow-up-fixes-for-bpf-syscall-common-attributes'

Leon Hwang says:

====================
bpf: Follow-up fixes for BPF syscall common attributes

Address sashiko reviews for BPF syscall common attributes series.

1. The tailing padding bytes in struct bpf_common_attr should be
   checked. [1]
2. There was a concurrent regression in syscall.c::map_create(). [2]
3. OPTS_VALID() was missing to validate the nested struct bpf_log_opts
   in libbpf. [3]
4. The token_fd should be -1 to avoid a valid token fd in test. [4]

A test is added to verify the fix #1.

The fix #2 is hard to be verified by test. So, I decide not to add a test
for it to avoid over-engineering.

Decide not to add a test for fix #3 to avoid over-engineering, as the
fix looks really simple.

Links:
[1] https://lore.kernel.org/bpf/20260513224823.6494FC19425@smtp.kernel.org/
[2] https://lore.kernel.org/bpf/20260512233658.CEED7C2BCB0@smtp.kernel.org/
[3] https://lore.kernel.org/bpf/20260512235629.C5CABC2BCB0@smtp.kernel.org/
[4] https://lore.kernel.org/bpf/20260513003358.55836C2BCB0@smtp.kernel.org/
====================

Link: https://patch.msgid.link/20260518145446.6794-1-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>