Fix name in pair_exp6_rx_kokkos

void partition_range( const int begin, const int end, int &thread_begin, int &thread_end, const int chunkSize = 1)

{

   int threadId = omp_get_thread_num();

   int nThreads = omp_get_nthreads();

   int nThreads = omp_get_num_threads();

   const int len = end - begin;

   const int nBlocks = (len + (chunkSize - 1)) / chunkSize;