drm/ttm: Wait for a BO to become idle before unbinding it from GTT

Fixes hangs under memory pressure, e.g. running the piglit test
tex3d-maxsize concurrently with other tests.

Fixes: 17d33bc9d6 ("drm/ttm: drop waiting for idle in ttm_bo_evict.")
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

include/drm/ttm/ttm_bo_driver.h

@@ -962,6 +962,7 @@ void ttm_mem_io_free(struct ttm_bo_device *bdev,
  *
  * @bo: A pointer to a struct ttm_buffer_object.
  * @evict: 1: This is an eviction. Don't try to pipeline.
+ * @interruptible: Sleep interruptible if waiting.
  * @no_wait_gpu: Return immediately if the GPU is busy.
  * @new_mem: struct ttm_mem_reg indicating where to move.
  *
@@ -976,7 +977,7 @@ void ttm_mem_io_free(struct ttm_bo_device *bdev,
  */
 
 extern int ttm_bo_move_ttm(struct ttm_buffer_object *bo,
-			   bool evict, bool no_wait_gpu,
+			   bool evict, bool interruptible, bool no_wait_gpu,
 			   struct ttm_mem_reg *new_mem);
 
 /**