[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/wdt285.c b/drivers/char/watchdog/wdt285.c
index 6555fb8..89a249e 100644
--- a/drivers/char/watchdog/wdt285.c
+++ b/drivers/char/watchdog/wdt285.c
@@ -137,7 +137,7 @@
 	       unsigned long arg)
 {
 	unsigned int new_margin;
-	int ret = -ENOIOCTLCMD;
+	int ret = -ENOTTY;
 
 	switch(cmd) {
 	case WDIOC_GETSUPPORT: