console: fix bug in *_erase_screen()

We must erase the whole screen and not only until the current cursor
position. Probably a copy-paste typo.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>

src/console.c

@@ -472,5 +472,5 @@ void kmscon_console_erase_screen(struct kmscon_console *con)
 		return;
 
 	kmscon_buffer_erase_region(con->cells, 0, 0,
-					con->cells_x - 1, con->cursor_y);
+					con->cells_x - 1, con->cells_y - 1);
 }