libefivar: 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

Note that the link above no longer exists.  The commit message was kept
verbatim.  An archive of the bug report can be found at:
https://web.archive.org/web/20240714192319/https://bugzilla.tianocore.org/show_bug.cgi?id=1373

Obtained from:	https://github.com/tianocore/edk2/commit/9344f0921518309295da89c221d10cbead8531aa

Reviewed by: imp
Pull Request: https://github.com/freebsd/freebsd-src/pull/1894

lib/libefivar/uefi-dputil.c

@@ -37,7 +37,7 @@
 
 /*
  * Taken from MdePkg/Library/UefiDevicePathLib/DevicePathUtilities.c
- * hash 2f7a96d6ec13b292d6f31295f3195913921173e1 2019-Feb-21
+ * hash 9344f0921518309295da89c221d10cbead8531aa 2019-Apr-09
  */
 
 /** @file
@@ -51,13 +51,7 @@
   on a Handle.
 
   Copyright (c) 2006 - 2018, 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
 
 **/