ARM: omap1: Remove reliance on GPIO numbers from SX1

It appears this happens because the OMAP driver now
allocates GPIO numbers dynamically, so all that is
references by number is a bit up in the air.

Utilize the NULL device to define some board-specific
GPIO lookups and use these to immediately look up the
same GPIOs, convert to IRQ numbers and pass as resources
to the devices. This is ugly but should work.

Fixes: 92bf78b3 ("gpio: omap: use dynamic allocation of base")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>