drm/i915/overlay: Use the recommended page alignment for physical regs

Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_overlay.c

@@ -1406,7 +1406,7 @@ void intel_setup_overlay(struct drm_device *dev)
 	if (OVERLAY_NEEDS_PHYSICAL(dev)) {
 		ret = i915_gem_attach_phys_object(dev, reg_bo,
 						  I915_GEM_PHYS_OVERLAY_REGS,
-						  0);
+						  PAGE_SIZE);
                 if (ret) {
                         DRM_ERROR("failed to attach phys overlay regs\n");
                         goto out_free_bo;