ath5k: ensure led name is null terminated

Add the missing null termination after strncpy().

This isn't actually a buffer overflow in this case since we use
snprintf() appropriately to fill the buffer passed by the caller,
but in the interest of not turning this into a bug down the road,
go ahead and force termination here.

Found by Coverity.
Signed-off-by: Bob Copeland <me@bobcopeland.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath5k/led.c

@@ -130,6 +130,7 @@ ath5k_register_led(struct ath5k_hw *ah, struct ath5k_led *led,
 
 	led->ah = ah;
 	strncpy(led->name, name, sizeof(led->name));
+	led->name[sizeof(led->name)-1] = 0;
 	led->led_dev.name = led->name;
 	led->led_dev.default_trigger = trigger;
 	led->led_dev.brightness_set = ath5k_led_brightness_set;