pinctrl: rockchip: generalize bank-quirks

Upcoming Rockchip SoCs have additional quirks to handle. Currently they would
be handled by giving the bank a special compatible property. But the nature
of the new quirks would require a lot of them. Also as we want to move to the
separate dw_gpio driver in the future, these bank-definitions should be
extended at all.

Describing the bank quirks this way also enables us to deprecate the special
bank compatible string for bank0 on rk3188 and simplify the handling code.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>