1. Add CPU arch type in Mailbox, debug agent will not access HOB if CPU arch changed.
2. Updated DxeDebugAgentLib instance to copy DebugPortHandler buffer into allocated ACPIMemoryNVS besides the mailbox.
3. Remove deprecated SendingPacket from mailbox.

Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14302 6f19259b-4bc3-4df7-8a09-765794883524
Check-in missing part at r14302.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@14303 6f19259b-4bc3-4df7-8a09-765794883524