powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn

powerpc/powernv/idoa: Remove unnecessary pcidev from pci_dn

BugLink: https://bugs.launchpad.net/bugs/1819989
The pcidev value stored in pci_dn is only used for NPU/NPU2
initialization. We can easily drop the cached pointer and
use an ancient helper - pci_get_domain_bus_and_slot() instead in order
to reduce complexity.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Russell Currey <ruscur@russell.cc>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 902bdc57451c2c64aa139bbe24067f70a186db0a)
Signed-off-by: Jose Ricardo Ziviani <joserz@linux.ibm.com>
Acked-by: Kamal Mostafa <kamal@canonical.com>
Acked-by: Kleber Souza <kleber.souza@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>