ARM: sa1100/neponset: switch PCMCIA to MAX1600 library and gpiod APIs

Convert Neponset to use the gpiod API to specify which GPIOs are used
for PCMCIA, and use the MAX1600 power switch library for Neponset,
simplifying the neponset pcmcia driver as a result.

Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>