Add enable_ms to jsm driver

This fixes a crash observed when non-existant enable_ms function is
called for jsm driver.

Signed-off-by: Scott Kilau <Scott.Kilau@digi.com>
Signed-off-by: Paul Larson <pl@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/serial/jsm/jsm_tty.c

@@ -161,6 +161,11 @@ static void jsm_tty_stop_rx(struct uart_port *port)
 	channel->ch_bd->bd_ops->disable_receiver(channel);
 }
 
+static void jsm_tty_enable_ms(struct uart_port *port)
+{
+	/* Nothing needed */
+}
+
 static void jsm_tty_break(struct uart_port *port, int break_state)
 {
 	unsigned long lock_flags;
@@ -345,6 +350,7 @@ static struct uart_ops jsm_ops = {
 	.start_tx	= jsm_tty_start_tx,
 	.send_xchar	= jsm_tty_send_xchar,
 	.stop_rx	= jsm_tty_stop_rx,
+	.enable_ms	= jsm_tty_enable_ms,
 	.break_ctl	= jsm_tty_break,
 	.startup	= jsm_tty_open,
 	.shutdown	= jsm_tty_close,