ath79: fix pinmux for ar933x devices

ath79: fix pinmux for ar933x devices

Properly disable the SoC's internal Switch LEDs on the pinmux.
Devices that previously called ath79_gpio_function_disable for
the switch LEDs, just need to reference switch_led_pins in the
pinctrl-0 property of the gpio-leds node.

Signed-off-by: Paul Wassi <p.wassi@gmx.at>
[changed desired pinctrl register value from 0x1f to proper 0xf8]
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
[renamed pinmux name to switch_led_disable_pins to make purpose more clear]
Signed-off-by: Petr Štetiar <ynezz@true.cz>