{mb,nb,soc}: Remove references to pci_bus_default_ops()

pci_bus_default_ops() is the default anyway.

Change-Id: I5306d3feea3fc583171d8c865abbe0864b6d9cc6
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/26055
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/apollolake/chip.c

@@ -132,7 +132,6 @@ static struct device_operations pci_domain_ops = {
 	.enable_resources = NULL,
 	.init = NULL,
 	.scan_bus = pci_domain_scan_bus,
-	.ops_pci_bus = pci_bus_default_ops,
 	.acpi_name = &soc_acpi_name,
 };