For replace function, when target Ffs and new ffs are with same size, the output file can not be generated successfully. This patch fixes this issue. Cc: Rebecca Cran <rebecca@bsdio.com> Cc: Bob Feng <bob.c.feng@intel.com> Cc: Liming Gao <gaoliming@byosoft.com.cn> Signed-off-by: Yuwei Chen <yuwei.chen@intel.com> Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn> Reviewed-by: Bob Feng <bob.c.feng@intel.com>