Kokkos: Mark HWLOC as a TriBITS TPL as well (trilinos/Trilinos#11938)

It was reported by a Trilinos user in trilinos/Trilinos#11938 that after
removing Kokkos subpackages that their build of Trilinos failed and by marking
'HWLOC' as a TriBITS TPL this fixed the problem.  HWLOC has always been a
TriBITS TPL so it is not quite clear how this worked before this.

cmake/kokkos_tpls.cmake

@@ -31,7 +31,7 @@ FUNCTION(KOKKOS_TPL_OPTION PKG DEFAULT)
   ENDIF()
 ENDFUNCTION()
 
-KOKKOS_TPL_OPTION(HWLOC   Off)
+KOKKOS_TPL_OPTION(HWLOC   Off TRIBITS HWLOC)
 KOKKOS_TPL_OPTION(MEMKIND Off)
 IF(KOKKOS_ENABLE_MEMKIND)
   SET(KOKKOS_ENABLE_HBWSPACE ON)