Fix quantized_w8a32_conv1d fusion and operator

[ethansfng]

Summary:

1. Python fusion pass (fusion_pass.py): The permute nodes created in
   get_args_and_kwargs_mixed_w8a32_conv were missing val metadata, causing
   SpecViolationError during ExportedProgram validation. Added val computation
   using fake_mode, matching the pattern used by AddmmPattern.

2. C++ operators (generic + HiFi): cnn_step was called once with wrong
   dimensions (input length instead of kernel_size for d1), only producing
   out_channels values instead of the full output. Fixed to loop over output
   time steps, calling cnn_step per position with correct kernel_size, then
   scattering to NCL output layout.

Differential Revision: D92565258

[pytorch-bot]

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❌ 2 New Failures

As of commit 354a924 with merge base 7823792 ():

NEW FAILURES - The following jobs have failed:

• pull / test-samsung-models-linux / linux-job (gh)
  RuntimeError: Command docker exec -t 3bdf7869a47dcd36ab46d90d46802544190c81073e91a7884d8b809c9eb9e3b3 /exec failed with exit code 1
• pull / test-samsung-quantmodels-linux / linux-job (gh)
  RuntimeError: Command docker exec -t 7bb37f17f3251eeea747e623268465ab460353f2a222994cf411b505f5b0f332 /exec failed with exit code 1

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@ethansfng has exported this pull request. If you are a Meta employee, you can view the originating Diff in D92565258.

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