rtc: at91sam9: Fix missing spin_lock_init()

Author: Wei Yongjun <weiyj.lk@gmail.com>

The driver allocates the spinlock but not initialize it.
Use spin_lock_init() on it to initialize it correctly.

This is detected by Coccinelle semantic patch.

Signed-off-by: Wei Yongjun 
Signed-off-by: Alexandre Belloni 
 drivers/rtc/rtc-at91sam9.c | 1 +
 1 file changed, 1 insertion(+)
diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index 99732e6..7418a76 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -375,6 +375,7 @@ static int at91_rtc_probe(struct platform_device *pdev)
 	if (!rtc)
 		return -ENOMEM;
+	spin_lock_init(&rtc->lock);
 	rtc->irq = irq;
 	/* platform setup code should have handled this; sigh */