rtc: sun6i: ensure rtc is kfree'd on error

The error return path on clk_data allocation failure does not kfree
the allocated rtc object. Fix this with a kfree of rtc on the error
exit path.

Detected by CoverityScan, CID#1452264 ("Resource Leak")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>

drivers/rtc/rtc-sun6i.c

@@ -201,8 +201,10 @@ static void __init sun6i_rtc_clk_init(struct device_node *node)
 
 	clk_data = kzalloc(sizeof(*clk_data) + (sizeof(*clk_data->hws) * 2),
 			   GFP_KERNEL);
-	if (!clk_data)
+	if (!clk_data) {
+		kfree(rtc);
 		return;
+	}
 
 	spin_lock_init(&rtc->lock);