OvmfPkg: add Tcg2PhysicalPresenceLibNull when !TPM2_ENABLE

This NULL library will let us call
Tcg2PhysicalPresenceLibProcessRequest() unconditionally from
BdsPlatform when building without TPM2_ENABLE.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[lersek@redhat.com: replace MdeModulePkg.dec w/ MdePkg.dec]
Reviewed-by: Laszlo Ersek <lersek@redhat.com>

OvmfPkg/Library/Tcg2PhysicalPresenceLibNull/DxeTcg2PhysicalPresenceLib.c

@@ -0,0 +1,27 @@
+/** @file
+  NULL Tcg2PhysicalPresenceLib library instance
+
+  Copyright (c) 2018, Red Hat, Inc.
+  Copyright (c) 2013 - 2016, Intel Corporation. All rights reserved.<BR>
+  This program and the accompanying materials
+  are licensed and made available under the terms and conditions of the BSD License
+  which accompanies this distribution.  The full text of the license may be found at
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#include <Library/Tcg2PhysicalPresenceLib.h>
+
+VOID
+EFIAPI
+Tcg2PhysicalPresenceLibProcessRequest (
+  IN      TPM2B_AUTH                     *PlatformAuth  OPTIONAL
+  )
+{
+  //
+  // do nothing
+  //
+}