[TVMC][FIX] Compiler supports input with a slash

[leeexyz]

Hi, community,

When I use TVMC to compile a model trained on GPU, the name of input have a slash, such as "gpu_0/data_0": Var(gpu_0/data_0, ty=TensorType([1, 3, 224, 224], float32)), TVMC complains that cannot find such inputs in the graph, shows as below.

Traceback (most recent call last):
  File "/lib/python3.6/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/lib/python3.6/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "~/tvm/python/tvm/driver/tvmc/__main__.py", line 24, in <module>
    tvmc.main.main()
  File "~/tvm/python/tvm/driver/tvmc/main.py", line 94, in main
    sys.exit(_main(sys.argv[1:]))
  File "~/tvm/python/tvm/driver/tvmc/main.py", line 87, in _main
    return args.func(args)
  File "~/tvm/python/tvm/driver/tvmc/compiler.py", line 140, in drive_compile
    tvmc_model = frontends.load_model(args.FILE, args.model_format, args.input_shapes)
  File "~/tvm/python/tvm/driver/tvmc/frontends.py", line 376, in load_model
    mod, params = frontend.load(path, shape_dict, **kwargs)
  File "~/tvm/python/tvm/driver/tvmc/frontends.py", line 171, in load
    return relay.frontend.from_onnx(model, shape=shape_dict, **kwargs)
  File "~/tvm/python/tvm/relay/frontend/onnx.py", line 3605, in from_onnx
    mod, params = g.from_onnx(graph, opset)
  File "~/tvm/python/tvm/relay/frontend/onnx.py", line 3355, in from_onnx
    self._shape
AssertionError: User specified the shape for inputs that weren't found in the graph: {'data_0': [1, 3, 224, 224]}

This PR updates the RE to match such input name. :)

[leandron]

Thanks for the fix @leeexyz. I'm happy to merge it after CI.