[PATCH] cs5535_gpio.c: call cdev_del() during module_exit to unmap kobject references and other cleanups

During module unloading, cdev_del() must be called to unmap cdev related
kobject references and other cleanups(such as inode->i_cdev being set to
NULL) which prevents the OOPS upon subsequent loading, usage and unloading
of modules(as seen in the mail thread
http://marc.theaimsgroup.com/?l=linux-kernel&m=114533640609018&w=2).

Also, remove unneeded test of gpio_base.

Signed-off-by: Thayumanavar Sachithanantham <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/char/cs5535_gpio.c

···
 static void __exit cs5535_gpio_cleanup(void)
 {
 	dev_t dev_id = MKDEV(major, 0);
+
+	cdev_del(&cs5535_gpio_cdev);
 	unregister_chrdev_region(dev_id, CS5535_GPIO_COUNT);
-	if (gpio_base != 0)
-		release_region(gpio_base, CS5535_GPIO_SIZE);
+	release_region(gpio_base, CS5535_GPIO_SIZE);
 }
 
 module_init(cs5535_gpio_init);