bpf: fix references to free_bpf_prog_info() in comments

Comments in the verifier refer to free_bpf_prog_info() which
seems to have never existed in tree.  Replace it with
free_used_maps().

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

kernel/bpf/verifier.c

@@ -5055,7 +5055,7 @@ static int replace_map_fd_with_map_ptr(struct bpf_verifier_env *env)
 			/* hold the map. If the program is rejected by verifier,
 			 * the map will be released by release_maps() or it
 			 * will be used by the valid program until it's unloaded
-			 * and all maps are released in free_bpf_prog_info()
+			 * and all maps are released in free_used_maps()
 			 */
 			map = bpf_map_inc(map, false);
 			if (IS_ERR(map)) {
@@ -5821,7 +5821,7 @@ skip_full_check:
 err_release_maps:
 	if (!env->prog->aux->used_maps)
 		/* if we didn't copy map pointers into bpf_prog_info, release
-		 * them now. Otherwise free_bpf_prog_info() will release them.
+		 * them now. Otherwise free_used_maps() will release them.
 		 */
 		release_maps(env);
 	*prog = env->prog;