since the first character of the string cannot be found by multiple if statements, use elif to optomize the behavior. Cc: Yonghong Zhu <yonghong.zhu@intel.com> Cc: Liming Gao <liming.gao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jaben Carsey <jaben.carsey@intel.com> Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>