The call to gpiochip_add() is not currently error-checked. Add the
missing checking.
Signed-off-by: NStephen Warren <swarren@nvidia.com>
Reviewed-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>