[microNPU] Fixing imports in the entry point

This commit fixes errornous reporting that Vela
is missing if other import errors.

Change-Id: I8db97be10018726cf5d9483508321a176c212516

python/tvm/relay/op/contrib/ethosu.py

@@ -14,7 +14,7 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-# pylint: disable=ungrouped-imports
+# pylint: disable=ungrouped-imports, import-outside-toplevel
 """Arm(R) Ethos(TM)-U NPU supported operators."""
 import functools
 
@@ -36,14 +36,6 @@
     # rely on imports from ethos-u-vela, we protect them with the decorator @requires_vela
     # implemented below.
     from ethosu.vela import api as vapi  # type: ignore
-    from tvm.relay.backend.contrib.ethosu import preprocess
-    from tvm.relay.backend.contrib.ethosu.util import QConv2DArgs  # type: ignore
-    from tvm.relay.backend.contrib.ethosu.util import BiasAddArgs
-    from tvm.relay.backend.contrib.ethosu.util import RequantArgs
-    from tvm.relay.backend.contrib.ethosu.util import BinaryElementwiseArgs
-    from tvm.relay.backend.contrib.ethosu.util import DequantizeArgs
-    from tvm.relay.backend.contrib.ethosu.util import QuantizeArgs
-    from tvm.relay.backend.contrib.ethosu.util import get_dim_value
 except ImportError:
     vapi = None
 
@@ -116,6 +108,8 @@ def check_valid_dtypes(tensor_params: List[TensorParams], supported_dtypes: List
 
 def check_weights(weights: TensorParams, dilation: List[int]):
     """This function checks whether weight tensor is compatible with the NPU"""
+    from tvm.relay.backend.contrib.ethosu.util import get_dim_value
+
     dilated_height_range = (1, 64)
     dilated_hxw_range = (1, 64 * 64)
     weights_limit = 127 * 65536
@@ -200,6 +194,10 @@ class QnnConv2DParams:
 
     @requires_vela
     def __init__(self, func_body: tvm.relay.Function):
+        from tvm.relay.backend.contrib.ethosu.util import QConv2DArgs  # type: ignore
+        from tvm.relay.backend.contrib.ethosu.util import BiasAddArgs
+        from tvm.relay.backend.contrib.ethosu.util import RequantArgs
+
         activation = None
         if str(func_body.op) in self.activation_map.keys():
             activation = func_body
@@ -472,6 +470,8 @@ class BinaryElementwiseParams:
     """
 
     def __init__(self, func_body: Call, operator_type: str, has_quantization_parameters: bool):
+        from tvm.relay.backend.contrib.ethosu.util import BinaryElementwiseArgs
+
         clip = None
         if str(func_body.op) == "clip":
             clip = func_body
@@ -869,6 +869,9 @@ class AbsParams:
     composite_name = "ethos-u.abs"
 
     def __init__(self, func_body: Call):
+        from tvm.relay.backend.contrib.ethosu.util import QuantizeArgs
+        from tvm.relay.backend.contrib.ethosu.util import DequantizeArgs
+
         quantize = func_body
         abs_op = quantize.args[0]
         dequantize = abs_op.args[0]
@@ -1037,6 +1040,8 @@ def partition_for_ethosu(
     mod : IRModule
         The partitioned IRModule with external global functions
     """
+    from tvm.relay.backend.contrib.ethosu import preprocess
+
     if params:
         mod["main"] = bind_params_by_name(mod["main"], params)