arm64: Enable dynamic sched_domain flag setting

The patch lets the arch_topology driver take over setting of
sched_domain flags that should be detected dynamically based on the
actual system topology.

cc: Catalin Marinas <catalin.marinas@arm.com>
cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>