s390/vmlogrdr: change return value from -ENOSYS to -EOPNOTSUPP

Changing the return value of vmlogrdr_open() to -EOPNOTSUPP if O_NONBLOCK
is specified shouldn't have any negative side effects.
Any existing user wouldn't specify that flag since it wouldn't work anyway.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/char/vmlogrdr.c

@@ -321,7 +321,7 @@ static int vmlogrdr_open (struct inode *inode, struct file *filp)
 	 * only allow for blocking reads to be open
 	 */
 	if (filp->f_flags & O_NONBLOCK)
-		return -ENOSYS;
+		return -EOPNOTSUPP;
 
 	/* Besure this device hasn't already been opened */
 	spin_lock_bh(&logptr->priv_lock);