BaseTools: Replace BSD License with BSD+Patent License

https://bugzilla.tianocore.org/show_bug.cgi?id=1373

Replace BSD 2-Clause License with BSD+Patent License.  This change is
based on the following emails:

  https://lists.01.org/pipermail/edk2-devel/2019-February/036260.html
  https://lists.01.org/pipermail/edk2-devel/2018-October/030385.html

RFCs with detailed process for the license change:

  V3: https://lists.01.org/pipermail/edk2-devel/2019-March/038116.html
  V2: https://lists.01.org/pipermail/edk2-devel/2019-March/037669.html
  V1: https://lists.01.org/pipermail/edk2-devel/2019-March/037500.html

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Bob Feng <bob.c.feng@intel.com>

BaseTools/Tests/CheckUnicodeSourceFiles.py

@@ -3,13 +3,7 @@
 #
 #  Copyright (c) 2015, 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.
+#  SPDX-License-Identifier: BSD-2-Clause-Patent
 #
 
 ##