Philippe 26/06/2023: OpenACC: ice4_fast_rg: restore a necessary update for IGDRY (crash on Nvidia)

(cherry picked from commit 18a466fd)

src/MNH/ice4_fast_rg.f90

@@ -545,7 +545,8 @@ ELSE
 !$acc kernels
   PRG_TEND(:, IRRDRYG)=0.
 !$acc end kernels
-! acc update host( IGDRY )
+
+!$acc update host( IGDRY )
   !
   IF(IGDRY>0) THEN
     !$acc kernels