[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: Samuel Tardieu <sam@rfc1149.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

diff --git a/drivers/char/watchdog/wdrtas.c b/drivers/char/watchdog/wdrtas.c
index 5c38cdf..1d64e27 100644
--- a/drivers/char/watchdog/wdrtas.c
+++ b/drivers/char/watchdog/wdrtas.c
@@ -385,7 +385,7 @@
 		return put_user(wdrtas_interval, argp);
 
 	default:
-		return -ENOIOCTLCMD;
+		return -ENOTTY;
 	}
 }