um: switch to use of drivers/Kconfig

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

drivers/char/ttyprintk.c

@@ -170,7 +170,7 @@ static const struct tty_operations ttyprintk_ops = {
 	.ioctl = tpk_ioctl,
 };
 
-struct tty_port_operations null_ops = { };
+static struct tty_port_operations null_ops = { };
 
 static struct tty_driver *ttyprintk_driver;