Move CUDA/Complex.h to GPU/Complex.h, remove TensorReductionCuda.h
Move CUDA/Complex.h to GPU/Complex.h, remove TensorReductionCuda.h
The Complex.h
file applies equally to HIP/CUDA, so placing under the
generic GPU
folder.
The TensorReductionCuda.h
has already been deprecated, now removing
for the next Eigen version.