The motivation behind this patch and following patches is to extract
information about the platform in runtime rather than depending on
compile time macros such as FVP_CLUSTER_COUNT. This partially enables
us to use a single binary for a family of platforms which all have
similar hardware capabilities but differ in configurations.

we populate the data structure describing the power domain hierarchy
of the platform dynamically by querying the number of clusters and cpus
using fconf getter APIs. Compile time macro such as FVP_CLUSTER_COUNT
is still needed as it determines the size of related data structures.

Note that the cpu-map node in HW_CONFIG dts represents a logical
hierarchy of power domains of CPU. However, in reality, the power
domains may not have been physically built in such hierarchy.

Change-Id: Ibcbb5ca7b2c969f8ad03ab2eab289725245af7a9
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>