bpf: tools: Sync uapi bpf.h

Sync uapi bpf.h to tools/include/uapi/linux for
the new bpf_line_info.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>