sunsu: Fix use after free in su_remove().

Real serial port 'up' objects are statically allocated from an
array in the driver.  Keyboard and mouse ports, on the other
hand, are dynamically allocated.

Unfortunately, we free these dynamic 'up' objects before we unmap the
I/O registers.

Rearrange su_remove() so that this does not happen.

Noticed by Julia Lawall.

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/serial/sunsu.c

@@ -1500,20 +1500,25 @@ out_unmap:
 static int __devexit su_remove(struct of_device *op)
 {
 	struct uart_sunsu_port *up = dev_get_drvdata(&op->dev);
+	bool kbdms = false;
 
 	if (up->su_type == SU_PORT_MS ||
-	    up->su_type == SU_PORT_KBD) {
+	    up->su_type == SU_PORT_KBD)
+		kbdms = true;
+
+	if (kbdms) {
 #ifdef CONFIG_SERIO
 		serio_unregister_port(&up->serio);
 #endif
-		kfree(up);
-	} else if (up->port.type != PORT_UNKNOWN) {
+	} else if (up->port.type != PORT_UNKNOWN)
 		uart_remove_one_port(&sunsu_reg, &up->port);
-	}
 
 	if (up->port.membase)
 		of_iounmap(&op->resource[0], up->port.membase, up->reg_size);
 
+	if (kbdms)
+		kfree(up);
+
 	dev_set_drvdata(&op->dev, NULL);
 
 	return 0;