Philippe 20/06/2023: bugfix: ice4_fast_rg: correct mnh_expand_where loop size

(cherry picked from commit 9c064dd7)

src/MNH/ice4_fast_rg.f90

@@ -601,7 +601,7 @@ ELSE
       ZZW(I1(JJ)) = ZVEC3(JJ)
     END DO
     !
-    !$mnh_expand_where(JJ=1:IGDRY)
+    !$mnh_expand_where(JJ=1:ISIZE)
     WHERE(GDRY(:))
 #ifndef MNH_BITREP
       PRG_TEND(:, IRRDRYG) = XFRDRYG*ZZW(:)                    & ! RRDRYG