OvmfPkg: update PciHostBridgeDxe to use PlatformHasIoMmuLib

OvmfPkg: update PciHostBridgeDxe to use PlatformHasIoMmuLib

This patch enables PciHostBridgeDxe driver to use Platform IoMMU detection
library to ensure that PciHostBridgeDxe is run after platform IoMmuDxe
driver has checked whether platform need to install IOMMU protocol provider.

Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Suggested-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>