UefiCpuPkg SecCore: Adjust PeiTemporaryRamBase&Size to be 8byte aligned

As HOB which has 8byte aligned requirement will be built based on them
in PEI phase.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>