ACPI / hotplug / PCI: Always return success after adding a function

When a new ACPIPHP function is added by register_slot() and the
notify handler cannot be installed for it, register_slot() returns an
error status without cleaning up, which causes the entire namespace
walk in acpiphp_enumerate_slots() to be aborted, although it still
may be possible to successfully install the function notify handler
for other device objects under the given brigde.

To address this issue make register_slot() return success after
a new function has been added, even if the addition of the notify
handler for it has failed.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>

drivers/pci/hotplug/acpiphp_glue.c

@@ -325,10 +325,9 @@ register_slot(acpi_handle handle, u32 lvl, void *context, void **rv)
 
 		if (ACPI_FAILURE(status))
 			err("failed to register interrupt notify handler\n");
-	} else
-		status = AE_OK;
+	}
 
-	return status;
+	return AE_OK;
 
  err_exit:
 	bridge->nr_slots--;