leds: tca6507: silence an uninitialized variable warning

If choose_times() returns -EINVAL that means "c1" and "c2" haven't been
initialized.  I've added a check for that.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jacek Anaszewski <j.anaszewski@samsung.com>

drivers/leds/leds-tca6507.c

@@ -327,6 +327,8 @@ static void set_times(struct tca6507_chip *tca, int bank)
 	int result;
 
 	result = choose_times(tca->bank[bank].ontime, &c1, &c2);
+	if (result < 0)
+		return;
 	dev_dbg(&tca->client->dev,
 		"Chose on  times %d(%d) %d(%d) for %dms\n",
 		c1, time_codes[c1],