selftests: bpf: fix -Wformat-invalid-specifier for bpf_obj_id.c

Use standard C99 %zu for sizeof, not GCC's custom %Zu:
bpf_obj_id.c:76:48: warning: invalid conversion specifier 'Z'
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/prog_tests/bpf_obj_id.c

@@ -73,7 +73,7 @@ void test_bpf_obj_id(void)
 			  info_len != sizeof(struct bpf_map_info) ||
 			  strcmp((char *)map_infos[i].name, expected_map_name),
 			  "get-map-info(fd)",
-			  "err %d errno %d type %d(%d) info_len %u(%Zu) key_size %u value_size %u max_entries %u map_flags %X name %s(%s)\n",
+			  "err %d errno %d type %d(%d) info_len %u(%zu) key_size %u value_size %u max_entries %u map_flags %X name %s(%s)\n",
 			  err, errno,
 			  map_infos[i].type, BPF_MAP_TYPE_ARRAY,
 			  info_len, sizeof(struct bpf_map_info),
@@ -117,7 +117,7 @@ void test_bpf_obj_id(void)
 			  *(int *)(long)prog_infos[i].map_ids != map_infos[i].id ||
 			  strcmp((char *)prog_infos[i].name, expected_prog_name),
 			  "get-prog-info(fd)",
-			  "err %d errno %d i %d type %d(%d) info_len %u(%Zu) jit_enabled %d jited_prog_len %u xlated_prog_len %u jited_prog %d xlated_prog %d load_time %lu(%lu) uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) name %s(%s)\n",
+			  "err %d errno %d i %d type %d(%d) info_len %u(%zu) jit_enabled %d jited_prog_len %u xlated_prog_len %u jited_prog %d xlated_prog %d load_time %lu(%lu) uid %u(%u) nr_map_ids %u(%u) map_id %u(%u) name %s(%s)\n",
 			  err, errno, i,
 			  prog_infos[i].type, BPF_PROG_TYPE_SOCKET_FILTER,
 			  info_len, sizeof(struct bpf_prog_info),
@@ -185,7 +185,7 @@ void test_bpf_obj_id(void)
 		      memcmp(&prog_info, &prog_infos[i], info_len) ||
 		      *(int *)(long)prog_info.map_ids != saved_map_id,
 		      "get-prog-info(next_id->fd)",
-		      "err %d errno %d info_len %u(%Zu) memcmp %d map_id %u(%u)\n",
+		      "err %d errno %d info_len %u(%zu) memcmp %d map_id %u(%u)\n",
 		      err, errno, info_len, sizeof(struct bpf_prog_info),
 		      memcmp(&prog_info, &prog_infos[i], info_len),
 		      *(int *)(long)prog_info.map_ids, saved_map_id);
@@ -231,7 +231,7 @@ void test_bpf_obj_id(void)
 		      memcmp(&map_info, &map_infos[i], info_len) ||
 		      array_value != array_magic_value,
 		      "check get-map-info(next_id->fd)",
-		      "err %d errno %d info_len %u(%Zu) memcmp %d array_value %llu(%llu)\n",
+		      "err %d errno %d info_len %u(%zu) memcmp %d array_value %llu(%llu)\n",
 		      err, errno, info_len, sizeof(struct bpf_map_info),
 		      memcmp(&map_info, &map_infos[i], info_len),
 		      array_value, array_magic_value);