gpio: remove the obsolete MX35 3DS BOARD MC9S08DZ60 GPIO functions

Commit e1324ece ("ARM: imx: Remove i.MX35 board files") removes the
config MACH_MX35_3DS in arch/arm/mach-imx/Kconfig.

Hence, since then, the MX35 3DS BOARD MC9S08DZ60 GPIO functions are dead
code as its config GPIO_MC9S08DZ60 depends on the config MACH_MX35_3DS.

Luckily, ./scripts/checkkconfigsymbols.py warns on non-existing configs:

MACH_MX35_3DS
Referencing files: drivers/gpio/Kconfig

Remove the obsolete MX35 3DS BOARD MC9S08DZ60 GPIO functions.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>