libbpf: Mark bpf_object__find_program_by_title API deprecated.

Deprecate this API since v0.7.  All callers should move to
bpf_object__find_program_by_name if possible, otherwise use
bpf_object__for_each_program to find a program out from a given
section.

[0] Closes: https://github.com/libbpf/libbpf/issues/292

Signed-off-by: Kui-Feng Lee <kuifeng@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211214035931.1148209-5-kuifeng@fb.com

tools/lib/bpf/libbpf.h

@@ -227,6 +227,7 @@ struct btf;
 LIBBPF_API struct btf *bpf_object__btf(const struct bpf_object *obj);
 LIBBPF_API int bpf_object__btf_fd(const struct bpf_object *obj);
 
+LIBBPF_DEPRECATED_SINCE(0, 7, "use bpf_object__find_program_by_name() instead")
 LIBBPF_API struct bpf_program *
 bpf_object__find_program_by_title(const struct bpf_object *obj,
 				  const char *title);