MdeModulePkg/PciBus: do not improperly degrade resource

MdeModulePkg/PciBus: do not improperly degrade resource

PciBus driver originally always degrade (64->32) the MMIO resource
for PCI BAR when the PCI device contains option ROM.
But the degrade causes the PCI device can only use resource below 4GB
which makes the resource allocation fails when the PCI device wants
very big MMIO.
The patch follows the PI spec (ECR 1529) to honor the granularity
setting for PCI BAR from IncompatiblePciDeviceSupport so that even
for PCI device which contains option ROM, the degrade doesn't happen
if IncompatiblePciDeviceSupport returns 64 as granularity.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Jeff Fan <jeff.fan@intel.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>