rtc-tx4939: fix races around device registration

* Use its own spinlock instead of rtc->irq_lock
* Check pdata->rtc before calling rtc_update_irq
* Disable interrupt after rtc_device_unregister

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Alessandro Zummo <a.zummo@towertech.it>
Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 file changed