MdeModulePkg/Pci: Add DeviceSecurity support.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2303

Whenever a PCI device is discovered, PCI bus calls the
EDKII_DEVICE_SECURITY_PROTOCOL to authenticate it.
If the function returns success, the PCI bus allocates
the resource and installs the PCI_IO for the device.
If the function returns fail, the PCI bus skips the device.

It is similar to EFI_SECURITY_ARCH_PROTOCOL, which
is used to verify an EFI image.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Yun Lou <yun.lou@intel.com>
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>

MdeModulePkg/Bus/Pci/PciBusDxe/PciBus.c

@@ -8,7 +8,7 @@
   PCI Root Bridges. So it means platform needs install PCI Root Bridge IO protocol for each
   PCI Root Bus and install PCI Host Bridge Resource Allocation Protocol.
 
-Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
 SPDX-License-Identifier: BSD-2-Clause-Patent
 
 **/
@@ -37,7 +37,7 @@ UINT64                                        gAllZero             = 0;
 EFI_PCI_PLATFORM_PROTOCOL                     *gPciPlatformProtocol;
 EFI_PCI_OVERRIDE_PROTOCOL                     *gPciOverrideProtocol;
 EDKII_IOMMU_PROTOCOL                          *mIoMmuProtocol;
-
+EDKII_DEVICE_SECURITY_PROTOCOL                *mDeviceSecurityProtocol;
 
 GLOBAL_REMOVE_IF_UNREFERENCED EFI_PCI_HOTPLUG_REQUEST_PROTOCOL mPciHotPlugRequest = {
   PciHotPlugRequestNotify
@@ -293,6 +293,14 @@ PciBusDriverBindingStart (
           );
   }
 
+  if (mDeviceSecurityProtocol == NULL) {
+    gBS->LocateProtocol (
+          &gEdkiiDeviceSecurityProtocolGuid,
+          NULL,
+          (VOID **) &mDeviceSecurityProtocol
+          );
+  }
+
   if (PcdGetBool (PcdPciDisableBusEnumeration)) {
     gFullEnumeration = FALSE;
   } else {