OvmfPkg/License.txt: refresh the MIT license text and include the SPD…

…X ID

Refresh the MIT license text from <https://spdx.org/licenses/MIT.html>,
and add "SPDX-License-Identifier: MIT" for easier parsing by machines.

This follows the tree-wide adoption of "SPDX-License-Identifier"s, made
for <https://bugzilla.tianocore.org/show_bug.cgi?id=1373>; in particular:

- commit 304bff7 ("edk2: Change License.txt from 2-Clause BSD to
  BSD+Patent", 2019-04-09),

- commit 75fae50 ("OvmfPkg: Change License.txt from 2-Clause BSD to
  BSD+Patent", 2019-04-09).

Cc: Anthony Perard <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Jordan Justen <[email protected]>
Cc: Julien Grall <[email protected]>
Cc: Lars Kurth <[email protected]>
Cc: [email protected]
Bugzilla: https://bugzilla.tianocore.org/show_bug.cgi?id=1654
Signed-off-by: Laszlo Ersek <[email protected]>
Reviewed-by: Philippe Mathieu-Daude <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Reviewed-by: Anthony PERARD <[email protected]>

OvmfPkg/License.txt

@@ -57,15 +57,18 @@ are located in:
 - OvmfPkg/Include/IndustryStandard/Xen/
 - OvmfPkg/XenBusDxe/
 
+SPDX-License-Identifier: MIT
+
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
 in the Software without restriction, including without limitation the rights
 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 copies of the Software, and to permit persons to whom the Software is
 furnished to do so, subject to the following conditions:
 
-The above copyright notice and this permission notice shall be included in
-all copies or substantial portions of the Software.
+The above copyright notice and this permission notice (including the next
+paragraph) shall be included in all copies or substantial portions of the
+Software.
 
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,