ARM: OMAP: Use gpiolib with tps65010 for OSK 5912

Convert OSK board to use new tps65010 gpiolib support.  This
includes moving its LED support from leds-osk to gpio-leds,
giving more trigger options and a net platform code shrink.

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