leds: just ignore invalid GPIOs in leds-gpio

Fix build problems with leds-gpio:

  CC      drivers/leds/leds-gpio.o
drivers/leds/leds-gpio.c: In function 'create_gpio_led':
drivers/leds/leds-gpio.c:85: warning: 'return' with no value, in function returning non-void

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>

drivers/leds/leds-gpio.c

@@ -82,7 +82,7 @@ static int __devinit create_gpio_led(const struct gpio_led *template,
 	if (!gpio_is_valid(template->gpio)) {
 		printk(KERN_INFO "Skipping unavilable LED gpio %d (%s)\n", 
 				template->gpio, template->name);
-		return;
+		return 0;
 	}
 
 	ret = gpio_request(template->gpio, template->name);