staging: lustre: Move assignments out of function calls.

Assignments inside of function calls confuse the reader and should be
avoided, so it was moved out before the call.

Found with Coccinelle, semantic patch:
@@
identifier f;
expression e1, e2;
assignment operator a;
@@

+ e1 a e2;
f(...,
- (e1 a e2)
+ e1
 ,...);
Signed-off-by: Elise Lennion <elise.lennion@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/llite/vvp_io.c

@@ -450,7 +450,8 @@ static void vvp_io_advance(const struct lu_env *env,
 	struct vvp_io	 *vio = cl2vvp_io(env, ios);
 	CLOBINVRNT(env, obj, vvp_object_invariant(obj));
 
-	iov_iter_reexpand(vio->vui_iter, vio->vui_tot_count  -= nob);
+	vio->vui_tot_count -= nob;
+	iov_iter_reexpand(vio->vui_iter, vio->vui_tot_count);
 }
 
 static void vvp_io_update_iov(const struct lu_env *env,