fix sigmoid cudnn bug (#22439)

* Sigmoid bug fix, test=develop

* fix code format

test=develop
Co-authored-by: NManjunath Bhat <manjunathbhat9920@gmail.com>

paddle/fluid/operators/activation_cudnn_op.cu.cc

@@ -174,7 +174,7 @@ namespace ops = paddle::operators;
 #define FOR_EACH_CUDNN_OP_FUNCTOR(__macro)                        \
   __macro(relu, CudnnReluFunctor, CudnnReluGradFunctor);          \
   __macro(relu6, CudnnRelu6Functor, CudnnRelu6GradFunctor);       \
-  __macro(sigmoid, CudnnTanhFunctor, CudnnTanhGradFunctor); \
+  __macro(sigmoid, CudnnSigmoidFunctor, CudnnSigmoidGradFunctor); \
   __macro(tanh, CudnnTanhFunctor, CudnnTanhGradFunctor)
 
 #define REGISTER_ACTIVATION_CUDNN_KERNEL(act_type, functor, grad_functor) \