The PE for root bus (root PE) can be removed because of PCI hot
remove in EEH recovery path for fenced PHB error. We need update
@phb->root_pe_populated accordingly so that the root PE can be
populated again in forthcoming PCI hot add path. Also, the PE
shouldn't be destroyed as it's global and reserved resource.

Fixes: c5f7700b ("powerpc/powernv: Dynamically release PE")
Reported-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>