Philippe 03/04/2023: fix missing mg_finalise (forgotten commit)

src/MNH/finalize_mnh.f90

-!MNH_LIC Copyright 2021-2021 CNRS, Meteo-France and Universite Paul Sabatier
+!MNH_LIC Copyright 2021-2023 CNRS, Meteo-France and Universite Paul Sabatier
 !MNH_LIC This is part of the Meso-NH software governed by the CeCILL-C licence
 !MNH_LIC version 1. See LICENSE, CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt
 !MNH_LIC for details. version 1.
@@ -32,6 +32,9 @@ SUBROUTINE FINALIZE_MNH
 #endif
   USE MODE_MPPDB,            only: MPPDB_BARRIER
   USE MODE_MSG,              only: MSG_STATS
+#ifdef MNH_MGSOLVER
+  USE multigrid,             only: mg_finalise
+#endif
 
 #ifdef CPLOASIS
   USE MODI_SFX_OASIS_END
@@ -48,6 +51,9 @@ SUBROUTINE FINALIZE_MNH
 #ifdef MNH_OPENACC
   CALL PRINT_FLATPOOL_STATS()
 #endif
+#ifdef MNH_MGSOLVER
+  call mg_finalise()
+#endif
 
   !Print the number of printed messages via Print_msg
   CALL MSG_STATS()