update suppression

tools/dev/cppcheck/suppressions.txt

@@ -41,8 +41,8 @@ redundantAssignment:tests/main/driver_api/init_run_deinit.c
 redundantAssignment:tests/main/driver_api/run_driver.c
 
 uselessAssignmentPtrArg:mpi/src/starpu_mpi.c:171
-unreadVariable:mpi/src/starpu_mpi.c:986
-unusedVariable:mpi/src/starpu_mpi.c:987
+unreadVariable:mpi/src/starpu_mpi.c:991
+unusedVariable:mpi/src/starpu_mpi.c:992
 redundantAssignment:src/core/workers.c
 
 invalidPointerCast:src/core/perfmodel/perfmodel_nan.c:74