Fix of using of using in Atomic.h

template< typename T >

class Atomic< T, Devices::Sequential > : public Atomic< T, Devices::Host >

{

   using Base = Atomic< T, Devices::Host >;

   public:

   using Atomic;

   using operator=;

   using fetch_max;

   using fetch_min;

   using Base::Atomic;

   using Base::operator=;

   using Base::fetch_max;

   using Base::fetch_min;

};

template< typename T >