IntelFsp2Pkg: FSP_TEMP_RAM_INIT call must follow X64 Calling Convention

IntelFsp2Pkg: FSP_TEMP_RAM_INIT call must follow X64 Calling Convention

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=3926
This API accept one parameter using RCX and this is consumed
in mutiple sub functions.

Cc: Chasel Chiu <chasel.chiu@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Ashraf Ali S <ashraf.ali.s@intel.com>
Signed-off-by: cbduggap <chinni.b.duggapu@intel.com>
Reviewed-by: Chasel Chiu <chasel.chiu@intel.com>