Fix preprocessor condition on when to use fast float logistic implementation.

Eigen/src/Core/functors/UnaryFunctors.h

diff --git a/Eigen/src/Core/functors/UnaryFunctors.h b/Eigen/src/Core/functors/UnaryFunctors.h
index 4447b82..2f9b920 100644
--- a/Eigen/src/Core/functors/UnaryFunctors.h
+++ b/Eigen/src/Core/functors/UnaryFunctors.h
@@ -1126,7 +1126,7 @@
 
 // TODO(rmlarsen): Enable the following on host when integer_packet is defined
 // for the relevant packet types.
-#ifdef EIGEN_GPU_CC
+#ifndef EIGEN_GPUCC
 
 /** \internal
  * \brief Template specialization of the logistic function for float.