ppc/pnv: assign pnv-phb-root-port chassis/slot earlier

ppc/pnv: assign pnv-phb-root-port chassis/slot earlier

It is not advisable to execute an object_dynamic_cast() to poke into
bus->qbus.parent and follow it up with a C cast into the PnvPHB type we
think we got.

In fact this is not needed. There is nothing sophisticated being done
with the PHB object retrieved during root_port_realize() for both PHB3
and PHB4. We're retrieving a PHB reference just to access phb->chip_id
and phb->phb_id and use them to define the chassis/slot of the root
port.

phb->phb_id is already being passed to pnv_phb_attach_root_port() via
the 'index' parameter. Let's also add a 'chip_id' parameter to this
function and assign chassis and slot right there. This will spare us
from the hassle of accessing the PHB object inside realize().

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Frederic Barrat <fbarrat@linux.ibm.com>
Message-Id: <20220621173436.165912-4-danielhb413@gmail.com>