drm/selftests: drop use of drmP.h

Drop the single user of drmP.h - replace it with relevant includes.
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Alexandru-Cosmin Gheorghe <Alexandru-Cosmin.Gheorghe@arm.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190716064220.18157-11-sam@ravnborg.org

drivers/gpu/drm/selftests/test-drm_framebuffer.c

@@ -3,7 +3,12 @@
  * Test cases for the drm_framebuffer functions
  */
 
-#include <drm/drmP.h>
+#include <linux/kernel.h>
+
+#include <drm/drm_device.h>
+#include <drm/drm_mode.h>
+#include <drm/drm_fourcc.h>
+
 #include "../drm_crtc_internal.h"
 
 #include "test-drm_modeset_common.h"