There are Rockchip SoCs, namely the rk3188, that combine a set of
regular banks with banks that need special handling for some settings.

Therefore add the possibility for the driver to handle more than one
bank type.
Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>