This adds the mfd cell to use the gpio a and gpio b part
of the Nano River Technologies viperboard.
Signed-off-by: NLars Poeschel <poeschel@lemonage.de>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>