cpu-topology: Don't error on more than CONFIG_NR_CPUS CPUs in device tree

When the kernel is configured with CONFIG_NR_CPUS smaller than the
number of CPU nodes in the device tree(DT), all the CPU nodes parsing
done to fetch topology information will fail. This is not reasonable
as it is valid to have all the physical CPUs in the system in the DT.
Let us just skip such CPU DT nodes that are not used in the kernel
rather than returning an error.

Change-Id: Ic7c50afd52741eb2a472fe33d532835f767e8d1c
Signed-off-by: Shivnandan Kumar <quic_kshivnan@quicinc.com>