ARM: dts: rockchip: enable pwm3 as pwm regulator for rk3066a based boards

Rayeager/Bqcurie2/Marsboard use pwm3 modulate the vdd_logic voltage,
so enable it.

Signed-off-by: Andy Yan <andy.yan@rock-chips.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>