serial: core: Remove tty port activate() and shutdown() methods

serial core does not use tty_port_open() or tty_port_close(); serial
core defines and extends it's own tty open() and close() methods
(uart_open() and uart_close(), respectively).

Remove the tty_port activate() and shutdown() initializations, and
the uart_port_activate() function, which is never called.

NB: uart_port_shutdown() is used by uart_close() => uart_shutdown()
call chain (but not via the tty_port methods).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/serial_core.c

@@ -1530,11 +1530,6 @@ static void uart_hangup(struct tty_struct *tty)
 	mutex_unlock(&port->mutex);
 }
 
-static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
-{
-	return 0;
-}
-
 static void uart_port_shutdown(struct tty_port *port)
 {
 	struct uart_state *state = container_of(port, struct uart_state, port);
@@ -2377,8 +2372,6 @@ static const struct tty_operations uart_ops = {
 };
 
 static const struct tty_port_operations uart_port_ops = {
-	.activate	= uart_port_activate,
-	.shutdown	= uart_port_shutdown,
 	.carrier_raised = uart_carrier_raised,
 	.dtr_rts	= uart_dtr_rts,
 };