OvmfPkg: pull in CpuIo2Smm driver

OvmfPkg: pull in CpuIo2Smm driver

This driver provides EFI_SMM_CPU_IO2_PROTOCOL, which the SMM core depends
on in its gEfiDxeSmmReadyToLockProtocolGuid callback
(SmmReadyToLockHandler(), "MdeModulePkg/Core/PiSmmCore/PiSmmCore.c").

Approached on a higher level, this driver provides the SmmIo member of the
EFI_SMM_SYSTEM_TABLE2 (SMST).

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19044 6f19259b-4bc3-4df7-8a09-765794883524