drm/format_helper: Dual licence the file in GPL 2 and MIT

Contributors for this file are :
Gerd Hoffmann <[email protected]>
Maxime Ripard <[email protected]>
Noralf Trønnes <[email protected]>

Acked-by: Noralf Trønnes <[email protected]>
Acked-by: Gerd Hoffmann <[email protected]>
Acked-by: Maxime Ripard <[email protected]>
Signed-off-by: Emmanuel Vadot <[email protected]>
Signed-off-by: Daniel Vetter <[email protected]>
Link: https://patchwork.freedesktop.org/patch/msgid/[email protected]
diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c
index 0897cb9..3b818f2 100644
--- a/drivers/gpu/drm/drm_format_helper.c
+++ b/drivers/gpu/drm/drm_format_helper.c
@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+// SPDX-License-Identifier: GPL-2.0 or MIT
 /*
  * Copyright (C) 2016 Noralf Trønnes
  *