Permit MIT licenses when checking copyright

Some source files in TF-A are distributed under the terms of the MIT
license, as they are derived from other projects where the original
files are licensed under the MIT license instead of the BSD-3-Clause
license.

Change-Id: I48d78acd4c3a5de717bfe5273971e0fe8fc514aa
Signed-off-by: Chris Kay <chris.kay@arm.com>
1 file changed