All the machines using the MMCI are passing GPIOs for the
card detect and write protect using the device tree or
descriptor table (one single case, Integrator/AP IM-PD1).

Drop support for passing global GPIO numbers through
platform data, noone is using it.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>