BaseTools: Fix COMPRESS alignment incorrect issue

BaseTools: Fix COMPRESS alignment incorrect issue

Doesn't generate the correct alignment for the leaf section
in the compression section.
Below FFS rule doesn't work as the expectation.

[Rule.Common.PEIM.PE32]
  FILE PEIM = $(NAMED_GUID) {
    PEI_DEPEX PEI_DEPEX Optional $(INF_OUTPUT)/$(MODULE_NAME).depex
    COMPRESS {
      PE32   PE32  Align=Auto    $(INF_OUTPUT)/$(MODULE_NAME).efi
      UI     STRING="$(MODULE_NAME)" Optional
      VERSION  STRING="$(INF_VERSION)" Optional BUILD_NUM=$(BUILD_NUMBER)
    }
  }

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yunhua Feng <yunhuax.feng@intel.com>
Reviewed-by: Yonghong Zhu <yonghong.zhu@intel.com>