drm/ttm: remove NULL checks when calling ttm_tt_destroy

The function is a no-op with a NULL pointer.

Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_tt.c

@@ -168,7 +168,7 @@ void ttm_tt_destroy(struct ttm_tt *ttm)
 {
 	int ret;
 
-	if (unlikely(ttm == NULL))
+	if (ttm == NULL)
 		return;
 
 	if (ttm->state == tt_bound) {