drm: make drm_mm_init() return void

There is no reason to return "int" as this function never fails.
Furthermore, several drivers (ast, sis) already depend on this.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_mm.c

@@ -669,7 +669,7 @@ int drm_mm_clean(struct drm_mm * mm)
 }
 EXPORT_SYMBOL(drm_mm_clean);
 
-int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
+void drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 {
 	INIT_LIST_HEAD(&mm->hole_stack);
 	INIT_LIST_HEAD(&mm->unused_nodes);
@@ -690,8 +690,6 @@ int drm_mm_init(struct drm_mm * mm, unsigned long start, unsigned long size)
 	list_add_tail(&mm->head_node.hole_stack, &mm->hole_stack);
 
 	mm->color_adjust = NULL;
-
-	return 0;
 }
 EXPORT_SYMBOL(drm_mm_init);