OvmfPkg: PciHostBridgeLib: set bus, IO and 32-bit MMIO windows in RootBus

OvmfPkg: PciHostBridgeLib: set bus, IO and 32-bit MMIO windows in RootBus

The bus aperture is copied verbatim from InitRootBridge()
[OvmfPkg/PciHostBridgeDxe/PciHostBridge.c].

The IO and 32-bit MMIO apertures are matched to PlatformPei's settings.
PciHostBridgeLibDxe expects PciHostBridgeLib instances to advertize the
exact apertures.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Marcel Apfelbaum <marcel@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>