ppc/pnv: remove useless "core-pir" property alias.

ppc/pnv: remove useless "core-pir" property alias.

Commit 158e17a65e1a ("ppc/pnv: Link "chip" property to PnvCore::chip
pointer") introduced some cleanups of the PnvCore realize handler.
Let's continue by reworking a bit the interface of the PnvCore
handlers for the CPU threads. These changes make the "core-pir"
property alias unused. Remove it.

Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20200127144154.10170-3-clg@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>