add npu to supported devices

Author: ji-huazhong

bitsandbytes/__init__.py

@@ -25,6 +25,7 @@
 features = {"multi_backend"}
 supported_torch_devices = {
     "cuda",  # includes ROCm
+    "npu",  # Ascend NPU
     "xpu",  # Intel GPU
     "cpu",
 }