Previously [1], we were using bpf_probe_prog_type which returned a
bool, but the new libbpf_probe_bpf_prog_type can return a negative
error code on failure. This change decides for bpftool to declare
a program type is not available on probe failure.

[1] https://lore.kernel.org/bpf/20220202225916.3313522-3-andrii@kernel.org/Signed-off-by: Milan Landaverde <milan@mdaverde.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Quentin Monnet <quentin@isovalent.com>
Link: https://lore.kernel.org/bpf/20220331154555.422506-4-milan@mdaverde.com