ppc/pnv: Add P10 quad xscom model

ppc/pnv: Add P10 quad xscom model

Add a PnvQuad class for the P10 powernv machine. No xscoms are
implemented yet, but this allows them to be added.

The size is reduced to avoid the quad region from overlapping with the
core region.

  address-space: xscom-0
    0000000000000000-00000003ffffffff (prio 0, i/o): xscom-0
      0000000100000000-00000001000fffff (prio 0, i/o): xscom-quad.0
      0000000100108000-0000000100907fff (prio 0, i/o): xscom-core.3
      0000000100110000-000000010090ffff (prio 0, i/o): xscom-core.2
      0000000100120000-000000010091ffff (prio 0, i/o): xscom-core.1
      0000000100140000-000000010093ffff (prio 0, i/o): xscom-core.0

Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Message-ID: <20230704054204.168547-4-joel@jms.id.au>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>