Fix the bug that use same FMP_PAYLOAD in different capsule file. Because
in previous FMP generation, the FMP already be generated, so we don't
need to regenerate again.
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>