Inception_v4_vaiq_int8 model support

[AmosLewis]

Failer op in Inception_v4_vaiq_int8.default.onnx.torch.elide.mlir

• torch.aten.avg_pool2d to linalg SHARK-ModelDev#643
• others unkown

(mlir_venv) ➜  Inception_v4_vaiq_int8 git:(reduceprod) ✗ torch-mlir-opt --convert-torch-onnx-to-torch  --torch-decompose-complex-ops --cse --canonicalize --convert-torch-to-linalg ./Inception_v4_vaiq_int8.default.onnx.torch.elide.mlir > Inception_v4_vaiq_int8.default.onnx.linalg.mlir
./Inception_v4_vaiq_int8.default.onnx.torch.elide.mlir:1053:12: error: failed to legalize operation 'torch.aten.avg_pool2d' that was explicitly marked illegal
    %816 = torch.aten.avg_pool2d %656, %813, %815, %814, %false_224, %false_225, %none_226 : !torch.vtensor<[32,384,25,25],f32>, !torch.list<int>, !torch.list<int>, !torch.list<int>, !torch.bool, !torch.bool, !torch.none -> !torch.vtensor<[32,384,25,25],f32>
           ^
./Inception_v4_vaiq_int8.default.onnx.torch.elide.mlir:1053:12: note: see current operation: %3001 = "torch.aten.avg_pool2d"(%2081, %642, %172, %3000, %16, %16, %88) : (!torch.vtensor<[32,384,25,25],f32>, !torch.list<int>, !torch.list<int>, !torch.list<int>, !torch.bool, !torch.bool, !torch.none) -> !torch.vtensor<[32,384,25,25],f32>

[AmosLewis]

iree-org/iree#17832