TigerlakeOpenBoardPkg: Fix build errors with GCC5

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3224



- Fix the path of TigerLakeFspBinPkg
- Fix misuse of RETURN_ERROR
- Remove unused function CheckNationalSio.

Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Heng Luo <heng.luo@intel.com>
Signed-off-by: Takuto Naito <naitaku@gmail.com>
Reviewed-by: Heng Luo <heng.luo@intel.com>
Reviewed-by: Nate DeSimone <nathaniel.l.desimone@intel.com>