ARM: dts: NSP: Device Tree clean-ups

Minor changes to the Broadcom Northstar Plus device tree to make it more
organized and clean.  Firstly, move the GIC and L2 cache entries to be
sequential with respect to the memory addresses.  Secondly, modify the
address portion of the entry names to reflect the difference from the
range modification.

Signed-off-by: Jon Mason <jonmason@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>