staging: vc04_services: use DIV_ROUND_UP helper macro

Replace open-coded division calculation with the DIV_ROUND_UP
helper macro for better readability.
Issue found using coccinelle:
@@
expression n,d;
@@
(
- ((n + d - 1) / d)
+ DIV_ROUND_UP(n,d)
|
- ((n + (d - 1)) / d)
+ DIV_ROUND_UP(n,d)
)
Signed-off-by: Wambui Karuga <wambui.karugax@gmail.com>
Link: https://lore.kernel.org/r/20191013184750.32766-1-wambui.karugax@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/vc04_services/interface/vchiq_arm/vchiq_core.h

@@ -60,8 +60,8 @@ vchiq_static_assert(IS_POW2(VCHIQ_MAX_SLOTS_PER_SIDE));
 
 #define VCHIQ_SLOT_MASK        (VCHIQ_SLOT_SIZE - 1)
 #define VCHIQ_SLOT_QUEUE_MASK  (VCHIQ_MAX_SLOTS_PER_SIDE - 1)
-#define VCHIQ_SLOT_ZERO_SLOTS  ((sizeof(struct vchiq_slot_zero) + \
-	VCHIQ_SLOT_SIZE - 1) / VCHIQ_SLOT_SIZE)
+#define VCHIQ_SLOT_ZERO_SLOTS  DIV_ROUND_UP(sizeof(struct vchiq_slot_zero), \
+					    VCHIQ_SLOT_SIZE)
 
 #define VCHIQ_MSG_PADDING            0  /* -                                 */
 #define VCHIQ_MSG_CONNECT            1  /* -                                 */