IVGCVSW-7024 Add missing license info for reuse lint

Signed-off-by: Jim Flynn <jim.flynn@arm.com>
Change-Id: I97dee6982e0a7be01c13e9e803c0997547a39ff1
diff --git a/cmake/AddDllCopyCommands.cmake b/cmake/AddDllCopyCommands.cmake
index 671bc7d..525eec4 100644
--- a/cmake/AddDllCopyCommands.cmake
+++ b/cmake/AddDllCopyCommands.cmake
@@ -1,3 +1,7 @@
+#
+# Copyright © 2018-2021 Arm Ltd and Contributors. All rights reserved.
+# SPDX-License-Identifier: MIT
+#
 macro (addDllCopyCommand target sourceDebug sourceRelease)
     add_custom_command(TARGET ${target} POST_BUILD
         COMMAND ${CMAKE_COMMAND} -E copy_if_different