ARM/gpio: Push OMAP2 quirk down into TWL4030 driver

The TWL4030 GPIO driver has a custom platform data .set_up()
callback to call back into the platform and do misc stuff such
as hog and export a GPIO for WLAN PWR on a specific OMAP3 board.

Avoid all the kludgery in the platform data and the boardfile
and just put the quirks right into the driver. Make it
conditional on OMAP3.

I think the exported GPIO is used by some kind of userspace
so ordinary DTS hogs will probably not work.

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