rockchip: pinctrl: rk3399: add the of-platdata support

Do not use the API which of-platdata not support.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Added rockchip tag:
Signed-off-by: Simon Glass <sjg@chromium.org>