drm/ttm: soften TTM warnings

QXL indeed unrefs pinned BOs and the warnings are spamming peoples log files.

Make sure we warn only once until the QXL driver is fixed.
Signed-off-by: Christian König <christian.koenig@amd.com>
References: https://lore.kernel.org/lkml/YD+eYcMMcdlXB8PY@alley/
Link: https://patchwork.freedesktop.org/patch/422834/Reviewed-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -136,7 +136,8 @@ void ttm_bo_move_to_lru_tail(struct ttm_buffer_object *bo,
 	struct ttm_bo_device *bdev = bo->bdev;
 	struct ttm_resource_manager *man;
 
-	dma_resv_assert_held(bo->base.resv);
+	if (!bo->deleted)
+		dma_resv_assert_held(bo->base.resv);
 
 	if (bo->pin_count) {
 		ttm_bo_del_from_lru(bo);
@@ -508,8 +509,11 @@ static void ttm_bo_release(struct kref *kref)
 		 * Make pinned bos immediately available to
 		 * shrinkers, now that they are queued for
 		 * destruction.
+		 *
+		 * FIXME: QXL is triggering this. Can be removed when the
+		 * driver is fixed.
 		 */
-		if (WARN_ON(bo->pin_count)) {
+		if (WARN_ON_ONCE(bo->pin_count)) {
 			bo->pin_count = 0;
 			ttm_bo_move_to_lru_tail(bo, &bo->mem, NULL);
 		}