gpio: pc104: Mask PC/104 drivers via PC104 Kconfig option

PC/104 drivers should be hidden on machines which do not support PC/104
devices. This patch adds the PC104 Kconfig option as a dependency for
the relevant PC/104 device driver Kconfig options.

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Alexandre Courbot <gnurou@gmail.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>