vt: remove lines parameter from scrollback

It is always called with 0, so remove the parameter and pass the
default down to scrolldelta without checking.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/tty/vt/keyboard.c b/drivers/tty/vt/keyboard.c
index f973bfc..cd08c10 100644
--- a/drivers/tty/vt/keyboard.c
+++ b/drivers/tty/vt/keyboard.c
@@ -579,7 +579,7 @@
 
 static void fn_scroll_back(struct vc_data *vc)
 {
-	scrollback(vc, 0);
+	scrollback(vc);
 }
 
 static void fn_show_mem(struct vc_data *vc)