REMOVE OMAP LEGACY CODE: Remove gpio-switch code

This code is not going to mainline based on earlier comments
on LKML and from David Brownell. For more details, please see:

http://thread.gmane.org/gmane.linux.kernel/809866

So far it looks like the gpio-switch code should be split to
two parts:

- Input events should handled with gpio_keys.c

- Toggling of GPIO values from userspace should be handlled
  via gpiolib

Patches against the mainline kernel are welcome as always!

Signed-off-by: Tony Lindgren <tony@atomide.com>