Per FDF spec, INF statement must use a .inf file, we add this error
check.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
(cherry picked from commit a87e79d9d6)