drm: use DIV_ROUND_UP helper macro for calculations

Replace open coded divisor calculations with the DIV_ROUND_UP kernel
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>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20191025094907.3582-1-wambui.karugax@gmail.com

drivers/gpu/drm/drm_agpsupport.c

@@ -212,7 +212,7 @@ int drm_agp_alloc(struct drm_device *dev, struct drm_agp_buffer *request)
 	if (!entry)
 		return -ENOMEM;
 
-	pages = (request->size + PAGE_SIZE - 1) / PAGE_SIZE;
+	pages = DIV_ROUND_UP(request->size, PAGE_SIZE);
 	type = (u32) request->type;
 	memory = agp_allocate_memory(dev->agp->bridge, pages, type);
 	if (!memory) {
@@ -325,7 +325,7 @@ int drm_agp_bind(struct drm_device *dev, struct drm_agp_binding *request)
 	entry = drm_agp_lookup_entry(dev, request->handle);
 	if (!entry || entry->bound)
 		return -EINVAL;
-	page = (request->offset + PAGE_SIZE - 1) / PAGE_SIZE;
+	page = DIV_ROUND_UP(request->offset, PAGE_SIZE);
 	retcode = drm_bind_agp(entry->memory, page);
 	if (retcode)
 		return retcode;