Fix cortex_m test failures from D106339880

Differential Revision: D106408368

Pull Request resolved: #19783

Author: SS-JIA

backends/cortex_m/passes/BUCK

@@ -36,6 +36,7 @@ fbcode_target(_kind = runtime.python_library,
         "decompose_hardswish_pass.py",
         "decompose_mean_pass.py",
         "quantized_clamp_activation_pass.py",
+        "scratch_buffer_sizes.py",
     ],
     deps=[
         "//caffe2:torch",

backends/cortex_m/passes/convert_to_cortex_m_pass.py

@@ -12,7 +12,7 @@
 import torch.fx
 from executorch.backends.arm._passes.arm_pass_utils import get_first_fake_tensor
 
-from executorch.backends.cortex_m.passes import CortexMPass
+from executorch.backends.cortex_m.passes.cortex_m_pass import CortexMPass
 from executorch.backends.cortex_m.passes.passes_utils import quantize_multiplier_aot
 from executorch.backends.cortex_m.passes.scratch_buffer_sizes import (
     required_cmsis_nn_buffer_sizes,