BaseTools: Enhance DEC Defines section format check

BaseTools: Enhance DEC Defines section format check

1. break if Dec Defines Section is missing
2. break if Dec have more than one Defines Section
3. break if Dec Defines Section have arch attribute
4. break if no section head, like as:
#[Defines]
 DEC_SPECIFICATION              = 0x00010005
 PACKAGE_NAME                   = Nt32Pkg

Cc: Liming Gao <liming.gao@intel.com>
Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yunhua Feng <yunhuax.feng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>