bpf: copy BPF token from main program to subprograms

bpf: copy BPF token from main program to subprograms

bpf_jit_subprogs() copies various fields from the main program's aux to
each subprogram's aux, but omits the BPF token. This causes
bpf_prog_kallsyms_add() to fail for subprograms loaded via BPF token,
as bpf_token_capable() falls back to capable() in init_user_ns when
token is NULL.

Copy prog->aux->token to func[i]->aux->token so that subprograms
inherit the same capability delegation as the main program.

Fixes: d79a35497547 ("bpf: Consistently use BPF token throughout BPF verifier logic")
Signed-off-by: Tao Chen <ctao@meta.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260415-subprog-token-fix-v4-1-9bd000e8b068@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>