libbpf: add BPF token support to bpf_prog_load() API

Wire through token_fd into bpf_prog_load().

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231130185229.2688956-16-andrii@kernel.org


Signed-off-by: Alexei Starovoitov <ast@kernel.org>