SecurityPkg: Update final event log calculation.

SecurityPkg: Update final event log calculation.

This patch updated final event log calculation based on
TCG EFI PROTOCOL rev9, 7.1.2 "All options implementation".
The previous logic is to save event to final event log
once GetEventLog() is called. 7.1.1 shows that we should
save event log to both normal even log area and final event
log area after GetEventLog() is called.
And there is no need to record TCG12 format log to final
event log area, and normal event log area can be BootServices
memory because OS will not access it directly.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: "Yao, Jiewen" <jiewen.yao@intel.com>
Reviewed-by: "Zhang, Chao B" <chao.b.zhang@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19661 6f19259b-4bc3-4df7-8a09-765794883524