ar71xx: Kernel support update tl-wr842n_v2 added missing usb led

Just a small oversight my part, added the support for the USB led
Signed-off-by: Martijn Zilverschoon <thefriedzombie@gmail.com>

Signed-off-by: Martijn Zilverschoon <thefriedzombie@gmail.com>
Patchwork: http://patchwork.openwrt.org/patch/4425/
Signed-off-by: Gabor Juhos <juhosg@openwrt.org>

SVN-Revision: 38946

target/linux/ar71xx/files/arch/mips/ath79/mach-tl-wr841n-v8.c

@@ -185,7 +185,7 @@ static void __init tl_wr842n_v2_setup(void)
 {
 	tl_ap123_setup();
 
-	ath79_register_leds_gpio(-1, ARRAY_SIZE(tl_wr841n_v8_leds_gpio) - 1,
+	ath79_register_leds_gpio(-1, ARRAY_SIZE(tl_wr841n_v8_leds_gpio),
 				 tl_wr841n_v8_leds_gpio);
 
 	ath79_register_gpio_keys_polled(1, TL_WR841NV8_KEYS_POLL_INTERVAL,