drivers base/arch_topology: Detect SD_SHARE_CAP_STATES flag

Detect and set the SD_SHARE_CAP_STATES sched_domain flag automatically
based on the cpufreq policy related_cpus mask. Since the sched_domain
flags functions don't take any parameters we have to assume that flags
are the same for sched_domains are the same level, i.e. platforms mixing
per-core and per-cluster DVFS is not supported.

cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>