add topk input shape of mmdnn

[zkh2016]

topk算子添加几个mmdnn模型中的shape：

#shape,       k,  axis
(-1, 32, 8, 64) 4 -1
(-1, 32, 13, 200) 18 -1
(-1, 32, 18, 128) 12 -1

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