drm/rcar-du: prepare for drmP.h removal from drm_modeset_helper.h

The use of drmP.h is discouraged and removal of it from
drm_modeset_helper.h caused rcar-du to fail to build.

This patch introduce the necessary fixes to prepare for the
drmP.h removal from drm_modeset_helper.h.

Build tested on arm allmodconfig/allyesconfig.

v2:
- new patch. Changes like drm_probe_helper and other
required several updates

Signed-off-by: Sam Ravnborg <[e-mail]>
Cc: Laurent Pinchart <[e-mail]>
Cc: Kieran Bingham <[e-mail]>
Cc: David Airlie <[e-mail]>
Cc: Daniel Vetter <[e-mail]>
Cc: [e-mail]
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/rcar-du/rcar_du_crtc.c

···
 
 #include <linux/clk.h>
 #include <linux/mutex.h>
+#include <linux/platform_device.h>
 #include <linux/sys_soc.h>
 
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
+#include <drm/drm_device.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_plane_helper.h>
+#include <drm/drm_vblank.h>
 
 #include "rcar_du_crtc.h"
 #include "rcar_du_drv.h"

drivers/gpu/drm/rcar-du/rcar_du_drv.c

···
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_fb_helper.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_probe_helper.h>
 

drivers/gpu/drm/rcar-du/rcar_du_kms.c

···
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
+#include <drm/drm_device.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_probe_helper.h>
+#include <drm/drm_vblank.h>
 
 #include <linux/of_graph.h>
 #include <linux/wait.h>

drivers/gpu/drm/rcar-du/rcar_du_plane.c

···
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
+#include <drm/drm_device.h>
 #include <drm/drm_fb_cma_helper.h>
+#include <drm/drm_fourcc.h>
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_plane_helper.h>
 

drivers/gpu/drm/rcar-du/rcar_du_vsp.c

···
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_plane_helper.h>
+#include <drm/drm_vblank.h>
 
 #include <linux/bitops.h>
 #include <linux/dma-mapping.h>