mfd: rk808: Add RK805 pinctrl support

Signed-off-by: Joseph Chen <chenjh@rock-chips.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lee Jones <lee.jones@linaro.org>