revert "rtc: cdev lock_kernel() pushdown"

Revert commit 51a776fa ("rtc: cdev
lock_kernel() pushdown").  The RTC framework does not need BKL
protection.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Alessandro Zummo <alessandro.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-dev.c

@@ -13,7 +13,6 @@
 
 #include <linux/module.h>
 #include <linux/rtc.h>
-#include <linux/smp_lock.h>
 #include "rtc-core.h"
 
 static dev_t rtc_devt;
@@ -27,11 +26,8 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 					struct rtc_device, char_dev);
 	const struct rtc_class_ops *ops = rtc->ops;
 
-	lock_kernel();
-	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags)) {
-		err = -EBUSY;
-		goto out;
-	}
+	if (test_and_set_bit_lock(RTC_DEV_BUSY, &rtc->flags))
+		return -EBUSY;
 
 	file->private_data = rtc;
 
@@ -41,13 +37,11 @@ static int rtc_dev_open(struct inode *inode, struct file *file)
 		rtc->irq_data = 0;
 		spin_unlock_irq(&rtc->irq_lock);
 
-		goto out;
+		return 0;
 	}
 
 	/* something has gone wrong */
 	clear_bit_unlock(RTC_DEV_BUSY, &rtc->flags);
-out:
-	unlock_kernel();
 	return err;
 }