PcAtChipsetPkg/PciHostBridgeDxe: Improve KVM FIFO I/O read/write performance

PcAtChipsetPkg/PciHostBridgeDxe: Improve KVM FIFO I/O read/write performance

KVM can substantially boost the speed of the rep insb/insw/insl
and rep outsb/outsw/outsl instructions by transferring up to
a page of data per VM trap.

This change adds assembly handling of the PCI Host Bridge
I/O FIFO Reads and Writes.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@13424 6f19259b-4bc3-4df7-8a09-765794883524