drm/panel: otm8009a: Adopt SPDX identifiers

Add SPDX identifiers to OriseTech OTM8009a panel driver.
Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180119110516.4916-1-philippe.cornu@st.com

drivers/gpu/drm/panel/panel-orisetech-otm8009a.c

+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (C) STMicroelectronics SA 2017
  *
  * Authors: Philippe Cornu <philippe.cornu@st.com>
  *          Yannick Fertre <yannick.fertre@st.com>
- *
- * License terms:  GNU General Public License (GPL), version 2
  */
+
 #include <drm/drmP.h>
 #include <drm/drm_mipi_dsi.h>
 #include <drm/drm_panel.h>