ppc/pnv: POWER9 XSCOM quad support

ppc/pnv: POWER9 XSCOM quad support

The POWER9 processor does not support per-core frequency control. The
cores are arranged in groups of four, along with their respective L2
and L3 caches, into a structure known as a Quad. The frequency must be
managed at the Quad level.

Provide a basic Quad model to fake the settings done by the firmware
on the Non-Cacheable Unit (NCU). Each core pair (EX) needs a special
BAR setting for the TIMA area of XIVE because it resides on the same
address on all chips.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20190307223548.20516-12-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>