fixes gpio_dev un/reload balancing

Signed-off-by: SHI Bin <shibin@ctsing.com>

SVN-Revision: 33183

target/linux/generic/files/drivers/char/gpio_dev.c

@@ -141,6 +141,8 @@ out:
 static int
 gpio_remove(struct platform_device *dev)
 {
+	device_destroy(gpiodev_class, MKDEV(dev_major, 0));
+	class_destroy(gpiodev_class);
 	unregister_chrdev(dev_major, DEVNAME);
 	return 0;
 }