[media] media: Include linux/kernel.h for DIV_ROUND_UP()

DIV_ROUND_UP() is defined in kernel.h which was not included by
media-entity.h. Do exactly that.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

include/media/media-entity.h

@@ -24,6 +24,7 @@
 #define _MEDIA_ENTITY_H
 
 #include <linux/bitops.h>
+#include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/media.h>