In SiRFprimaII, Each GPIO pin can be configured as input or output
independently. If a GPIO is configured as input, it can also be
enabled as an interrupt source (either edge or level triggered).

These pins must be either MUXed as GPIO or other function pads.
Signed-off-by: Yuping Luo <yuping.luo@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>