message: Add MFEM_DEVICE and MFEM_HOST_DEVICE when MFEM_USE_HIP
diff: #define MFEM_HIP_BLOCKS 256
  #ifdef MFEM_USE_HIP
  +#define MFEM_DEVICE __device__
  +#define MFEM_HOST_DEVICE __host__ __device__
  // Define a HIP error check macro, MFEM_GPU_CHECK(x), where x returns/is of
  // type 'hipError_t'. This macro evaluates 'x' and raises an error if the
  // result is not hipSuccess.
  