libbpf: Fix libbpf.map inheritance chain for LIBBPF_0.7.0

Ensure that LIBBPF_0.7.0 inherits everything from LIBBPF_0.6.0.

Fixes: dbdd2c7f ("libbpf: Add API to get/set log_level at per-program level")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220211205235.2089104-1-andrii@kernel.org

tools/lib/bpf/libbpf.map

@@ -438,4 +438,4 @@ LIBBPF_0.7.0 {
 		libbpf_probe_bpf_map_type;
 		libbpf_probe_bpf_prog_type;
 		libbpf_set_memlock_rlim_max;
-};
+} LIBBPF_0.6.0;