rtc-m41t80: use nonseekable_open()

Use nonseekable_open() for this since seeking is not supported anyway.
Signed-off-by: NJan Blunck <jblunck@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Gortmaker <p_gortmaker@yahoo.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/rtc/rtc-m41t80.c

@@ -595,10 +595,6 @@ static void wdt_disable(void)
 static ssize_t wdt_write(struct file *file, const char __user *buf,
 			 size_t count, loff_t *ppos)
 {
-	/*  Can't seek (pwrite) on this device
-	if (ppos != &file->f_pos)
-	return -ESPIPE;
-	*/
 	if (count) {
 		wdt_ping();
 		return 1;
@@ -707,7 +703,7 @@ static int wdt_open(struct inode *inode, struct file *file)
 		 */
 		wdt_is_open = 1;
 		unlock_kernel();
-		return 0;
+		return nonseekable_open(inode, file);
 	}
 	return -ENODEV;
 }