ar71xx: default to external USB power on RB-912UAG

There's a GPIO that can switch between power to USB pins for the
internal MiniPCIe slot or the external USB port.
People are more likely to use the external one so enable it by default.
Existing configurations should be unaffected

Signed-off-by: Felix Fietkau <nbd@nbd.name>

target/linux/ar71xx/base-files/etc/board.d/03_gpio_switches

@@ -25,7 +25,7 @@ wbs510)
 	;;
 rb-912uag-2hpnd|\
 rb-912uag-5hpnd)
-	ucidef_add_gpio_switch "usb_power_switch" "USB Power Switch" "52"
+	ucidef_add_gpio_switch "usb_power_switch" "USB Power Switch" "52" "1"
 	;;
 esac