SourceLevelDebugPkg/SecPeiDebugAgentLib: Restore CPU interrupt state

SourceLevelDebugPkg/SecPeiDebugAgentLib: Restore CPU interrupt state

In DEBUG_AGENT_INIT_POSTMEM_SEC case, caller may disable/restore CPU interrupt
to protect the stack/heap migration. SecPeiDebugAgentLib cannot always enable
CPU interrupt. Otherwise system may crash during stack/heap migration.
SecPeiDebugAgentLib should restore original CPU interrupt state in
DEBUG_AGENT_INIT_POSTMEM_SEC case.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jeff Fan <jeff.fan@intel.com>
Reviewed-by: Brian J. Johnson <bjohnson@sgi.com>
Tested-by: Brian J. Johnson <bjohnson@sgi.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17916 6f19259b-4bc3-4df7-8a09-765794883524