fix scalar pselect

Eigen/src/Core/GenericPacketMath.h

diff --git a/Eigen/src/Core/GenericPacketMath.h b/Eigen/src/Core/GenericPacketMath.h
index e1347b9..8bf8f90 100644
--- a/Eigen/src/Core/GenericPacketMath.h
+++ b/Eigen/src/Core/GenericPacketMath.h
@@ -580,21 +580,13 @@
 }
 
 // In the general case, use bitwise select.
-template <typename Packet, typename EnableIf = void>
+template <typename Packet>
 struct pselect_impl {
   static EIGEN_DEVICE_FUNC inline Packet run(const Packet& mask, const Packet& a, const Packet& b) {
     return por(pand(a, mask), pandnot(b, mask));
   }
 };
 
-// For scalars, use ternary select.
-template <typename Packet>
-struct pselect_impl<Packet, std::enable_if_t<is_scalar<Packet>::value>> {
-  static EIGEN_DEVICE_FUNC inline Packet run(const Packet& mask, const Packet& a, const Packet& b) {
-    return numext::equal_strict(mask, Packet(0)) ? b : a;
-  }
-};
-
 /** \internal \returns \a or \b for each field in packet according to \mask */
 template <typename Packet>
 EIGEN_DEVICE_FUNC inline Packet pselect(const Packet& mask, const Packet& a, const Packet& b) {