ARM: dts: logicpd-torpedo-som: Provide NAND ready pin

This was applied to a variety of omap3 boards, so it should
probably be applied here.  I did not test NAND performance, but
I tested this with UBI to confirm read/write didn't break.

Signed-off-by: Adam Ford <aford173@gmail.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>