pinctrl: rockchip: Remove of_match_ptr macro for DT only driver

This is a DT only driver and rockchip_pinctrl_dt_match is always compiled in.
Thus remove of_match_ptr macro.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>