Now that we have an accurate view of the physical topology
we need to represent it correctly to the scheduler. In the
case of NUMA in socket, we need to assure that the sched domain
we build for the MC layer isn't larger than the DIE above it.
To do this correctly, we should really base that on the cache
topology immediately below the NUMA node (for NUMA in socket)
or below the physical package for normal NUMA configurations.

This patch creates a set of early cache_siblings masks, then
when the scheduler requests the coregroup mask we pick the
smaller of the physical package siblings, or the numa siblings
and locate the largest cache which is an entire subset of
those siblings. If we are unable to find a proper subset of
cores then we retain the original behavior and return the
core_sibling list.

Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>