OMAPs can have 2 to 4 WAITPINs that can be used as general purpose
input if not used for memory wait state insertion.

The first user will be the OMAP NAND chip to get the NAND
read/busy status using gpiolib.
Signed-off-by: NRoger Quadros <rogerq@ti.com>
Acked-by: NRob Herring <robh@kernel.org>
Acked-by: NTony Lindgren <tony@atomide.com>