ARM: dts: BCM5301X: fix "reg" formatting in /memory node

This fixes warnings/errors like:
arch/arm/boot/dts/bcm4708-buffalo-wzr-1750dhp.dt.yaml: /: memory@0:reg:0: [0, 134217728, 2281701376, 402653184] is too long
        From schema: /lib/python3.6/site-packages/dtschema/schemas/reg.yaml

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>