[PATCH] rtc subsystem: use ENOIOCTLCMD and ENOTTY where appropriate

Appropriately use -ENOIOCTLCMD and -ENOTTY when the ioctl is not
implemented by a driver.

(akpm: we're not allowed to return -ENOIOCTLCMD to userspace.  This patch does
the right thing).

Signed-off-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/rtc/rtc-test.c b/drivers/rtc/rtc-test.c
index e1f7e8e..e1fa5fe 100644
--- a/drivers/rtc/rtc-test.c
+++ b/drivers/rtc/rtc-test.c
@@ -71,7 +71,7 @@
 		return 0;
 
 	default:
-		return -EINVAL;
+		return -ENOIOCTLCMD;
 	}
 }