ARM: OMAP: gpio object shrinkage, cleanup

More GPIO/IRQ cleanup:

  - compile-time removal of much useless code
      * mpuio support on non-OMAP1.
      * 15xx/730/24xx gpio support on 1610
      * 15xx/730/16xx gpio support on 24xx
      * etc

  - remove all BUG() calls, which are always bad news ... replaced some
    with normal fault reports for that call, others with WARN_ON(1).

  - small mpuio bugfix:  add missing set_type() method

Oh, and fix a minor merge issue: inode->u.generic_ip is now gone.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Tony Lindgren <tony@atomide.com>