Add the GPIO functionality for the Altera Arria10 MAX5 System Resource
Chip. The A10 MAX5 has 12 bits of GPIO assigned to switches, buttons,
and LEDs as a GPIO extender on the SPI bus.
Signed-off-by: NThor Thayer <tthayer@opensource.altera.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>i
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>