Created by: wangguibao

paddle/fluid/operators/math/cpu_lstm_compute.h contains an instatiation of lstm_compute_ctht: template<> void lstm_compute_ctht<float>(float* gates, const float* ct_1, float* ct, float* ht) {} When this header file are included in more than one C++ source, compiler will detect that there are multiple definitions.

This commit moves the instatiated lstm_compute_ctht to cpu_lstm_compute.cc, to avoid the multiple definition error.