ARM: 7841/1: sa1100: remove complex GPIO interface

The SA1100 was implementing its own variants of gpio_get_value()
and gpio_set_value() and only selectively falling back to
gpiolib for extended (EGPIO) handling. However the driver in
gpio/gpio-sa1100.c already handles the same functionality for
these lines, yet remain unused.

The only upside would be things like a timing-critical hotpath
on bit-banged GPIO, but that kind of things does not seem to
happen on these GPIOs, so it is not worth having the extra
complexity.

Tested with some buttons on the Compaq iPAQ H3630.

Cc: Kristoffer Ericson <kristoffer.ericson@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>