Add pinctrl support for Bitmain BM1880 SoC. The driver only handles
pinmuxing as the SoC is not capable of handling pinconf.
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
