For string op-code, the default string may not reach the maximum size, so when generating <AltResp> string, we should clean the value before setting the default string. https://bugzilla.tianocore.org/show_bug.cgi?id=375 Cc: Eric Dong <eric.dong@intel.com> Cc: Liming Gao <liming.gao@intel.com> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Dandan Bi <dandan.bi@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com>