add whitespace according to coding style. Cc: Maciej Rabeda <maciej.rabeda@linux.intel.com> Cc: Jiaxin Wu <jiaxin.wu@intel.com> Cc: Siyuan Fu <siyuan.fu@intel.com> Signed-off-by: Wenyi Xie <xiewenyi2@huawei.com> Reviewed-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>