bcm63xx: fix entering failsafe through button

gpio_keys_polled needs to be loaded in preinit for buttons to work for
entering failsafe.

SVN-Revision: 33653

target/linux/brcm63xx/base-files/lib/preinit/05_reset_button_brcm63xx

@@ -8,6 +8,7 @@ enable_reset_button() {
 		insmod input-polldev
 		insmod gpio_buttons
 		insmod button-hotplug
+		insmod gpio_keys_polled
 	fi
 }