rockchip: pinctrl: use per-SoC option names for Kconfig

The config options for pinctrl on the RK3188, RK3288, RK3328 and
RK3399 previously showed up in menuconfig with the generic string
descriptor "Rockchip pin control driver" requiring one to look through
the help/full description to identify which chip each menu entry was
for.

This change renames each option with the chip-name in the description
string to make it easy to identify the configuration options in
menuconfig.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Simon Glass <sjg@chromium.org>