IntelFsp2WrapperPkg: Add error handling for possible NULL ptr dereference

IntelFsp2WrapperPkg: Add error handling for possible NULL ptr dereference

Possible NULL pointer dereference for FspmHeaderPtr/FspsHeaderPtr in
module FspmWrapperPeim/FspsWrapperPeim.

Add error handling codes to avoid this issue.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Hao Wu <hao.a.wu@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Giri P Mudusuru <giri.p.mudusuru@intel.com>