【complex op】No.18 add complex support for silu (#57058)

paddle/phi/common/complex.h

@@ -496,16 +496,6 @@ HOSTDEVICE inline complex<T> log(const complex<T>& a) {
 #endif
 }
 
-template <typename T>
-HOSTDEVICE inline complex<T> exp(const complex<T>& a) {
-#if defined(PADDLE_WITH_CUDA_OR_HIP_COMPLEX) && \
-    (defined(__CUDA_ARCH__) || defined(__HIPCC__))
-  return complex<T>(thrust::exp(thrust::complex<T>(a)));
-#else
-  return complex<T>(std::exp(std::complex<T>(a)));
-#endif
-}
-
 template <typename T>
 inline std::ostream& operator<<(std::ostream& os, const complex<T>& a) {
   os << "real:" << a.real << " imag:" << a.imag;