video: rockchip: Restrict EDP, VOP, MIPI files to GPL-2.0

These files have a lot of code in common with their counterparts in
coreboot, especially in their earlier revisions:

                  U-Boot                  |                  coreboot
    --------------------------------------|--------------------------------------------
    drivers/video/rockchip/:              | src/soc/rockchip/:
    - rk_edp.c          (GPL-2.0+)        | - common/edp.c          (GPL-2.0-only)
       "                                  | - rk3288/display.c      (GPL-2.0-only)
       "                                  | - rk3399/display.c      (GPL-2.0-only)
    - rk_hdmi.h         (GPL-2.0+)        | (none)
    - rk_hdmi.c         (GPL-2.0+)        | - rk3288/hdmi.c         (GPL-2.0-or-later)
    - rk3288_hdmi.c     (GPL-2.0+)        | - rk3288/hdmi.c         (GPL-2.0-or-later)
    - rk3399_hdmi.c     (GPL-2.0+)        | (none)
    - rk_mipi.h         (GPL-2.0+)        | (none)
    - rk_mipi.c         (GPL-2.0+)        | - rk3399/mipi.c         (GPL-2.0-only)
    - rk3288_mipi.c     (GPL-2.0+)        | - rk3399/mipi.c         (GPL-2.0-only)
    - rk3399_mipi.c     (GPL-2.0+)        | - rk3399/mipi.c         (GPL-2.0-only)
    - rk_lvds.c         (GPL-2.0+)        | (none)
    - rk_vop.h          (GPL-2.0+)        | (none)
    - rk_vop.c          (GPL-2.0+)        | - common/vop.c          (GPL-2.0-only)
    - rk3288_vop.c      (GPL-2.0+)        | - common/vop.c          (GPL-2.0-only)
    - rk3399_vop.c      (GPL-2.0+)        | (none)
                                          |
    arch/arm/include/asm/arch-rockchip/:  | src/soc/rockchip/*/include/soc/*:
    - edp_rk3288.h      (GPL-2.0+)        | - common/.../edp.h      (GPL-2.0-only)
       "                                  | - rk3288/.../display.h  (GPL-2.0-only)
       "                                  | - rk3399/.../display.h  (GPL-2.0-only)
    - vop_rk3288.h      (GPL-2.0+)        | - common/.../vop.h      (GPL-2.0-only)

Restrict the licenses to match coreboot's so that changes from coreboot
can be imported to U-Boot as necessary. HDMI files are already 2.0+
there and rk_lvds.c has no counterpart, so keep them as is.

Cc: Simon Glass <sjg@chromium.org>
Cc: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Cc: Eric Gao <eric.gao@rock-chips.com>
Cc: Jacob Chen <jacob-chen@iotwrt.com>
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Kever Yang<kever.yang@rock-chips.com>
diff --git a/drivers/video/rockchip/rk3399_vop.c b/drivers/video/rockchip/rk3399_vop.c
index d5a7aa8..55d1be0 100644
--- a/drivers/video/rockchip/rk3399_vop.c
+++ b/drivers/video/rockchip/rk3399_vop.c
@@ -1,4 +1,4 @@
-// SPDX-License-Identifier: GPL-2.0+
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Copyright (c) 2017 Theobroma Systems Design und Consulting GmbH
  * Copyright (c) 2015 Google, Inc