fix mountpoint test to not prevemt mkfs_xxx from making image in any file

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

util-linux/mkfs_vfat.c

@@ -279,7 +279,7 @@ int mkfs_vfat_main(int argc UNUSED_PARAM, char **argv)
 		)
 			bb_error_msg_and_die("will not try to make filesystem on full-disk device (use -I if wanted)");
 		// can't work on mounted filesystems
-		if (find_mount_point(device_name))
+		if (find_mount_point(device_name, 0))
 			bb_error_msg_and_die("can't format mounted filesystem");
 #endif
 		// get true sector size