drm: shmobile: Reduce include dependencies

This file doesn't need anything provided by <linux/kernel.h>.
All it needs are some types, which are provided by <drm/drm_mode.h>.

Drop unneeded <linux/kernel.h> completely.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200422125201.37618-1-andriy.shevchenko@linux.intel.com

include/linux/platform_data/shmob_drm.h

@@ -10,8 +10,6 @@
 #ifndef __SHMOB_DRM_H__
 #define __SHMOB_DRM_H__
 
-#include <linux/kernel.h>
-
 #include <drm/drm_mode.h>
 
 enum shmob_drm_clk_source {