rtc: don't return -EBUSY when mutex_lock_interruptible() fails

It was pointed out that the RTC framework handles its mutex locks oddly
...  returning -EBUSY when interrupted.  This fixes that by returning the
value of mutex_lock_interruptible() (i.e.  -EINTR).

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rtc/rtc-dev.c b/drivers/rtc/rtc-dev.c
index 0a870b7..ae3bd4d 100644
--- a/drivers/rtc/rtc-dev.c
+++ b/drivers/rtc/rtc-dev.c
@@ -221,7 +221,7 @@
 
 	err = mutex_lock_interruptible(&rtc->ops_lock);
 	if (err)
-		return -EBUSY;
+		return err;
 
 	/* check that the calling task has appropriate permissions
 	 * for certain ioctls. doing this check here is useful