[WATCHDOG] use ENOTTY instead of ENOIOCTLCMD in ioctl()

Return ENOTTY instead of ENOIOCTLCMD in user-visible ioctl() results

The watchdog drivers used to return ENOIOCTLCMD for bad ioctl() commands.
ENOIOCTLCMD should not be visible by the user, so use ENOTTY instead.
Signed-off-by: NSamuel Tardieu <sam@rfc1149.net>
Signed-off-by: NWim Van Sebroeck <wim@iguana.be>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>

drivers/char/watchdog/w83697hf_wdt.c

@@ -233,7 +233,7 @@ wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 	}
 
 	default:
-	  return -ENOIOCTLCMD;
+	  return -ENOTTY;
 	}
 	return 0;
 }