Fix typo in error message in tools/fs_config/fs_config_generator.py.

            caps_split = caps.split(',')

            for cap in caps_split:

                if cap not in caps_dict:

                    sys.exit('Unkonwn cap "%s" found!' % cap)

                    sys.exit('Unknown cap "%s" found!' % cap)

                caps_value += 1 << caps_dict[cap]

        path_length_with_null = len(path) + 1