drm/i915: Assert internal objects are page aligned

Internal objects must be passed a page-aligned size. Check it.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170116145242.13875-1-chris@chris-wilson.co.ukReviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/i915_gem_internal.c

@@ -156,6 +156,7 @@ i915_gem_object_create_internal(struct drm_i915_private *i915,
 	struct drm_i915_gem_object *obj;
 
 	GEM_BUG_ON(!size);
+	GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE));
 
 	if (overflows_type(size, obj->base.size))
 		return ERR_PTR(-E2BIG);