[SERIAL] Make port->ops constant

No one should write to the port->ops structure, so make it constant.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/serial/serial_core.c

@@ -1870,7 +1870,7 @@ int uart_suspend_port(struct uart_driver *drv, struct uart_port *port)
 	mutex_lock(&state->mutex);
 
 	if (state->info && state->info->flags & UIF_INITIALIZED) {
-		struct uart_ops *ops = port->ops;
+		const struct uart_ops *ops = port->ops;
 
 		spin_lock_irq(&port->lock);
 		ops->stop_tx(port);
@@ -1932,7 +1932,7 @@ int uart_resume_port(struct uart_driver *drv, struct uart_port *port)
 	}
 
 	if (state->info && state->info->flags & UIF_INITIALIZED) {
-		struct uart_ops *ops = port->ops;
+		const struct uart_ops *ops = port->ops;
 		int ret;
 
 		ops->set_mctrl(port, 0);

include/linux/serial_core.h

@@ -257,7 +257,7 @@ struct uart_port {
 	unsigned int		mctrl;			/* current modem ctrl settings */
 	unsigned int		timeout;		/* character-based timeout */
 	unsigned int		type;			/* port type */
-	struct uart_ops		*ops;
+	const struct uart_ops	*ops;
 	unsigned int		custom_divisor;
 	unsigned int		line;			/* port index */
 	unsigned long		mapbase;		/* for ioremap */