ARM: dts: Enable NAND support on bcm911360_entphn

This patch enables NAND support on Broadcom Cygnus form factor board
(bcm911360_entphn)

Signed-off-by: Ray Jui <rjui@broadcom.com>
Reviewed-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>