xen/dts: Don't check the number of address and size cells in process_cpu_node

xen/dts: Don't check the number of address and size cells in process_cpu_node

CPU nodes are not required to have #address-cells == 1 and #size-cells == 0, so
don't check for that (see Linux Documentation/devicetree/booting-without-of.txt
Section III.5.a).

In some OMAP5 device, tree, these 2 properties are not correctly set. Therefore,
Xen will only able to handle 1 CPU.

Signed-off-by: Julien Grall <julien.grall@linaro.org>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
CC: andrii.anisov@globallogic.com
CC: baozich@gmail.com