libbpf: Add support for task local storage

Updates the bpf_probe_map_type API to also support
BPF_MAP_TYPE_TASK_STORAGE similar to other local storage maps.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-4-kpsingh@chromium.org