drm: Make drm_crtc_helper_disable() return void

The function can never fail, and always returns 0, so it may just as
well not return anything.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_crtc_helper.c

@@ -381,8 +381,7 @@ done:
 }
 EXPORT_SYMBOL(drm_crtc_helper_set_mode);
 
-
-static int
+static void
 drm_crtc_helper_disable(struct drm_crtc *crtc)
 {
 	struct drm_device *dev = crtc->dev;
@@ -411,7 +410,6 @@ drm_crtc_helper_disable(struct drm_crtc *crtc)
 	}
 
 	__drm_helper_disable_unused_functions(dev);
-	return 0;
 }
 
 /**
@@ -462,7 +460,8 @@ int drm_crtc_helper_set_config(struct drm_mode_set *set)
 				(int)set->num_connectors, set->x, set->y);
 	} else {
 		DRM_DEBUG_KMS("[CRTC:%d] [NOFB]\n", set->crtc->base.id);
-		return drm_crtc_helper_disable(set->crtc);
+		drm_crtc_helper_disable(set->crtc);
+		return 0;
 	}
 
 	dev = set->crtc->dev;