-WShadow errors

[thomaspj101796]

I get -WShadow build errors when compiling from tensorflow/lite/kernels/internal/reference/mul.h and tensorflow/lite/kernels/internal/reference/sub.h from a few functions that use the word 'params' twice in the header. I worked around this issue by changing the const ArithmeticParams& params to const ArithmeticParams& params1 and its subsequent calls to params1 where it occurs.