libbpf: Deprecate bpf_program__get_prog_info_linear

As part of the road to libbpf 1.0, and discussed in libbpf issue tracker
[0], bpf_program__get_prog_info_linear and its associated structs and
helper functions should be deprecated. The functionality is too specific
to the needs of 'perf', and there's little/no out-of-tree usage to
preclude introduction of a more general helper in the future.

  [0] Closes: https://github.com/libbpf/libbpf/issues/313

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211101224357.2651181-5-davemarchevsky@fb.com

tools/lib/bpf/libbpf.h

@@ -918,12 +918,15 @@ struct bpf_prog_info_linear {
 	__u8			data[];
 };
 
+LIBBPF_DEPRECATED_SINCE(0, 6, "use a custom linear prog_info wrapper")
 LIBBPF_API struct bpf_prog_info_linear *
 bpf_program__get_prog_info_linear(int fd, __u64 arrays);
 
+LIBBPF_DEPRECATED_SINCE(0, 6, "use a custom linear prog_info wrapper")
 LIBBPF_API void
 bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear);
 
+LIBBPF_DEPRECATED_SINCE(0, 6, "use a custom linear prog_info wrapper")
 LIBBPF_API void
 bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);