PCI: pciehp: Stop disabling notifications during init

During pciehp initialization, we previously wrote two hotplug commands:

  pciehp_probe
    pcie_init
      pcie_disable_notification
        pcie_write_cmd           # command 1
    pcie_init_notification
      pcie_enable_notification
        pcie_write_cmd           # command 2

For controllers with errata like Intel CF118, we previously waited for a
timeout before issuing the second hotplug command because the first command
only updates interrupt enable bits and is not a "real" hotplug command, so
the controller doesn't report Command Completed for it.

But there's no need to disable notifications in the first place.  If BIOS
left them enabled, we could easily take an interrupt before disabling them,
so there's no benefit in disabling them for the tiny window before we
enable them.

Drop the unnecessary pcie_disable_notification() call.

[bhelgaas: changelog]
Link: http://www.intel.com/content/www/us/en/processors/xeon/xeon-e7-v2-spec-update.html
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/hotplug/pciehp_hpc.c

@@ -793,9 +793,6 @@ struct controller *pcie_init(struct pcie_device *dev)
 		PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
 		PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC);
 
-	/* Disable software notification */
-	pcie_disable_notification(ctrl);
-
 	ctrl_info(ctrl, "Slot #%d AttnBtn%c AttnInd%c PwrInd%c PwrCtrl%c MRL%c Interlock%c NoCompl%c LLActRep%c\n",
 		(slot_cap & PCI_EXP_SLTCAP_PSN) >> 19,
 		FLAG(slot_cap, PCI_EXP_SLTCAP_ABP),