print message to inform that GPU package (instead of Kokkos) is used for LAMMPS

[xwuupb]

No description provided.

[ocaisa]

I made some tiny changes to make both the GPU package and Kokkos package branches consistent

[xwuupb]

thanks @ocaisa !
I will also PR the LAMMPS easyconfig files for the GPU package later, because currently only the KOKKOS-* variants are available for LAMMPS easyconfig files and my preliminary benchmarks show that the GPU-CUDA build provides much higher performance than the KOKKOS-* variants.

[ocaisa]

We did a good few studies when preparing http://www.hpc-carpentry.org/tuning_lammps/ and found the only major differences to be when the GPU package uses single precision (IIRC). I agree the other variants should be added, as which is better I believe depends on your use case (and Kokkos should improve the more recent the LAMMPS version).

Thanks for the PR, and for agreeing to create the easyconfig PRs!