The following build warning is seen with W=1:

  DTC     arch/arm/boot/dts/imx6sll-kobo-clarahd.dtb
arch/arm/boot/dts/e60k02.dtsi:51.9-53.4: Warning (unit_address_vs_reg): /memory: node has a reg or ranges property, but no unit name

Pass the memory unit address to fix the problem.

While at it, also pass 'device_type = "memory"', which is recommended
for memory nodes.
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Tested-by: Andreas Kemnade <andreas@kemnade.info>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>