MdeModulePkg/PeiCore: Fix the debug info of PEI temp heap length

MdeModulePkg/PeiCore: Fix the debug info of PEI temp heap length

(HandoffInformationTable->EfiFreeMemoryBottom - Private->HobList.Raw)
is the PEI temp heap used instead of the length of PEI temp heap.

The length of PEI temp heap should be:
(HandoffInformationTable->EfiFreeMemoryTop - Private->HobList.Raw)

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Cinnamon Shia <cinnamon.shia@hpe.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19762 6f19259b-4bc3-4df7-8a09-765794883524