drm/ttm: set TTM_OPT_FLAG_FORCE_ALLOC in ttm_bo_force_list_clean

Because ttm_bo_force_list_clean() is only called on two occasions:
1. By ttm_bo_evict_mm() during suspend.
2. By ttm_bo_clean_mm() when the driver unloads.
On both cases we absolutely don't want any memory allocation failure.
Signed-off-by: Roger He <Hongbo.He@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_bo.c

@@ -1344,7 +1344,11 @@ EXPORT_SYMBOL(ttm_bo_create);
 static int ttm_bo_force_list_clean(struct ttm_bo_device *bdev,
 				   unsigned mem_type)
 {
-	struct ttm_operation_ctx ctx = { false, false };
+	struct ttm_operation_ctx ctx = {
+		.interruptible = false,
+		.no_wait_gpu = false,
+		.flags = TTM_OPT_FLAG_FORCE_ALLOC
+	};
 	struct ttm_mem_type_manager *man = &bdev->man[mem_type];
 	struct ttm_bo_global *glob = bdev->glob;
 	struct dma_fence *fence;