omap3: Free Beagle rev gpios when they are read, so others can read them later

Free Beagle rev gpios when they are read, so others can read them later

Signed-off-by: Tasslehoff Kjappfot <tasskjapp@gmail.com>
[tony@atomide.com: updated comments]
Signed-off-by: Tony Lindgren <tony@atomide.com>