drm/hisilicon/kirin: 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 kirin to fail to build.

This patch introduce the necessary fixes to prepare for the
drmP.h removal from drm_modeset_helper.h.
List of include files sorted alphabetically.

Build tested on arm x86 allmodconfig using the following hack
to the Kconfig file:

| -       depends on DRM && OF && ARM64
| +       depends on DRM && OF && (ARM64 || (X86_64 && COMPILE_TEST))

Build failed on 32bit ARM - so the X86_64 hack was required.
The COMPILE_TEST hack is not submitted as the preferred fix
is something where we have coverage on 32bit ARM too.

v2:
- Sort list of include files
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Xinliang Liu <z.liuxinliang@hisilicon.com>
Cc: Rongrong Zou <zourongrong@gmail.com>
Cc: Xinwei Kong <kong.kongxinwei@hisilicon.com>
Cc: Chen Feng <puck.chen@hisilicon.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190119084014.5355-3-sam@ravnborg.org

drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c

@@ -17,12 +17,17 @@
 
 #include <linux/clk.h>
 #include <linux/component.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
 
-#include <drm/drm_of.h>
+#include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc_helper.h>
-#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_device.h>
 #include <drm/drm_encoder_slave.h>
-#include <drm/drm_atomic_helper.h>
+#include <drm/drm_mipi_dsi.h>
+#include <drm/drm_of.h>
+#include <drm/drm_print.h>
 
 #include "dw_dsi_reg.h"