powerpc/powernv: Exclude root bus in pnv_pci_reset_secondary_bus()

The function pnv_pci_reset_secondary_bus() is called like below.
It's impossible for call the function on root bus. So it's safe
to remove the root bus case in the function. No functional changes
introduced.

   pci_parent_bus_reset() / pci_bus_reset() / pci_try_reset_bus()
   pci_reset_bridge_secondary_bus()
   pcibios_reset_secondary_bus()
   pnv_pci_reset_secondary_bus()

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/platforms/powernv/eeh-powernv.c

@@ -868,16 +868,8 @@ static int pnv_eeh_bridge_reset(struct pci_dev *dev, int option)
 
 void pnv_pci_reset_secondary_bus(struct pci_dev *dev)
 {
-	struct pci_controller *hose;
-
-	if (pci_is_root_bus(dev->bus)) {
-		hose = pci_bus_to_host(dev->bus);
-		pnv_eeh_root_reset(hose, EEH_RESET_HOT);
-		pnv_eeh_root_reset(hose, EEH_RESET_DEACTIVATE);
-	} else {
-		pnv_eeh_bridge_reset(dev, EEH_RESET_HOT);
-		pnv_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE);
-	}
+	pnv_eeh_bridge_reset(dev, EEH_RESET_HOT);
+	pnv_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE);
 }
 
 static void pnv_eeh_wait_for_pending(struct pci_dn *pdn, const char *type,