The GPIO_CONTROL macro returns the control register offset when given a
GPIO number.

Update the argument name in the macro to reflect that it takes in a
GPIO number and not a bank.
Signed-off-by: NMarkus Mayer <markus.mayer@linaro.org>
Reviewed-by: NTim Kryger <tim.kryger@linaro.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>