ARM: dts: overo: fix gpmc nand cs0 range

The gpmc ranges property for NAND at CS0 has been broken since it was
first added.

This currently prevents the nand gpmc child node from being probed:

	omap-gpmc 6e000000.gpmc: /ocp/gpmc@6e000000/nand@0,0 has
	malformed 'reg' property

and consequently the NAND device from being registered.

Fixes: 98ce6007

 ("ARM: dts: overo: Support PoP NAND")
Cc: stable <stable@vger.kernel.org>	# 4.3
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>