[S390] Fix sparse warnings.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index f496f23..2971804 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -437,7 +437,7 @@
 {
 	struct string *s;
 
-	tp->rcl_walk = 0;
+	tp->rcl_walk = NULL;
 	if (len <= 0)
 		return;
 	if (tp->rcl_nr >= tp->rcl_max) {
@@ -466,12 +466,12 @@
 		else if (!list_empty(&tp->rcl_lines))
 			tp->rcl_walk = tp->rcl_lines.prev;
 		s = tp->rcl_walk ? 
-			list_entry(tp->rcl_walk, struct string, list) : 0;
+			list_entry(tp->rcl_walk, struct string, list) : NULL;
 		if (tp->rcl_walk) {
 			s = list_entry(tp->rcl_walk, struct string, list);
 			tty3270_update_prompt(tp, s->string, s->len);
 		} else
-			tty3270_update_prompt(tp, 0, 0);
+			tty3270_update_prompt(tp, NULL, 0);
 		tty3270_set_timer(tp, 1);
 	}
 	spin_unlock_bh(&tp->view.lock);
@@ -553,7 +553,7 @@
 	 * has to be emitted to the tty and for 0x6d the screen
 	 * needs to be redrawn.
 	 */
-	input = 0;
+	input = NULL;
 	len = 0;
 	if (tp->input->string[0] == 0x7d) {
 		/* Enter: write input to tty. */
@@ -567,7 +567,7 @@
 			tty3270_update_status(tp);
 		}
 		/* Clear input area. */
-		tty3270_update_prompt(tp, 0, 0);
+		tty3270_update_prompt(tp, NULL, 0);
 		tty3270_set_timer(tp, 1);
 	} else if (tp->input->string[0] == 0x6d) {
 		/* Display has been cleared. Redraw. */
@@ -808,8 +808,8 @@
 	tp = (struct tty3270 *) view;
 	tty = tp->tty;
 	if (tty) {
-		tty->driver_data = 0;
-		tp->tty = tp->kbd->tty = 0;
+		tty->driver_data = NULL;
+		tp->tty = tp->kbd->tty = NULL;
 		tty_hangup(tty);
 		raw3270_put_view(&tp->view);
 	}
@@ -948,8 +948,8 @@
 		return;
 	tp = (struct tty3270 *) tty->driver_data;
 	if (tp) {
-		tty->driver_data = 0;
-		tp->tty = tp->kbd->tty = 0;
+		tty->driver_data = NULL;
+		tp->tty = tp->kbd->tty = NULL;
 		raw3270_put_view(&tp->view);
 	}
 }
@@ -1673,7 +1673,7 @@
 		new = L_ECHO(tty) ? TF_INPUT: TF_INPUTN;
 		if (new != tp->inattr) {
 			tp->inattr = new;
-			tty3270_update_prompt(tp, 0, 0);
+			tty3270_update_prompt(tp, NULL, 0);
 			tty3270_set_timer(tp, 1);
 		}
 	}
@@ -1759,7 +1759,7 @@
 tty3270_notifier(int index, int active)
 {
 	if (active)
-		tty_register_device(tty3270_driver, index, 0);
+		tty_register_device(tty3270_driver, index, NULL);
 	else
 		tty_unregister_device(tty3270_driver, index);
 }
@@ -1818,7 +1818,7 @@
 
 	raw3270_unregister_notifier(tty3270_notifier);
 	driver = tty3270_driver;
-	tty3270_driver = 0;
+	tty3270_driver = NULL;
 	tty_unregister_driver(driver);
 	tty3270_del_views();
 }