pnv: Fix some error handling cpu realize()

pnv: Fix some error handling cpu realize()

In pnv_core_realize() we call two functions with an Error * parameter in
succession, which will go badly if they both cause errors.  In fact, a
failure in either of them indicates a qemu internal error, so we can just
use &error_abort in both cases.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Greg Kurz <groug@kaod.org>