Fix the following configuration error:
drivers/pinctrl/sunxi/Kconfig:3:error: recursive dependency detected!
drivers/pinctrl/sunxi/Kconfig:3: symbol PINCTRL_SUNXI is selected by PINCTRL_SUN4I_A10
drivers/pinctrl/sunxi/Kconfig:9: symbol PINCTRL_SUN4I_A10 default value contains PINCTRL_SUNXI
Add a new intermedia PINCTRL_SUNXI_COMMON, that superseeds the PINCTRL_SUNXI
one.
We still need to keep PINCTRL_SUNXI at the moment in order to preserve
bisectability. Indeed, during that merge window, we also introduced the
MACH_SUN* symbols. Since it's going through different trees, we can't rely on
the fact that the options will be there, while ARCH_SUNXI still select
PINCTRL_SUNXI.