MdeModulePkg/XhciDxe: enable 64-bit PCI DMA

PCI controller drivers must set the EFI_PCI_IO_ATTRIBUTE_DUAL_ADDRESS_CYCLE
attribute if the controller supports 64-bit DMA addressing.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Feng Tian <feng.tian@Intel.com>

MdeModulePkg/Bus/Pci/XhciDxe/Xhci.h

@@ -256,6 +256,8 @@ struct _USB_XHCI_INSTANCE {
   // The array supports up to 255 devices, entry 0 is reserved and should not be used.
   //
   USB_DEV_CONTEXT           UsbDevContext[256];
+
+  BOOLEAN                   Support64BitDma; // Whether 64 bit DMA may be used with this device
 };