ARM: OMAP: Use gpiolib

Update OMAP to use the new GPIO implementation framework.  This is just a
quick'n'dirty update ... more code could now be removed, ideally as part
of cleaning up the entire OMAP GPIO infrastructure ...

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>