Use multiple inheritance to remove accelerator_kokkos.h out of region.h and kspace.h

src/region.cpp

@@ -142,15 +142,6 @@ int Region::match(double x, double y, double z)
   return !(inside(x,y,z) ^ interior);
 }
 
-/* ----------------------------------------------------------------------
-   generate error if Kokkos function defaults to base class
-------------------------------------------------------------------------- */
-
-void Region::match_all_kokkos(int, DAT::tdual_int_1d)
-{
-  error->all(FLERR,"Can only use Kokkos supported regions with Kokkos package");
-}
-
 /* ----------------------------------------------------------------------
    generate list of contact points for interior or exterior regions
    if region has variable shape, invoke shape_update() once per timestep