device/pci_device: Remove useless pci_bus_ops_pci

The struct (formerly assigned to default_pci_ops_bus.ops_pci) only
contained a NULL (well, 0) pointer for the set_subsystem callback, but
usage of that callback is guarded with NULL checks when it is used,
therefore it can be removed.

TEST=still compiles

Change-Id: I3943c8ae73b95e744a317264d7ceb8929cb28341
Signed-off-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41432
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/device/pci_device.c

@@ -770,17 +770,12 @@ struct device_operations default_pci_ops_dev = {
 };
 
 /** Default device operations for PCI bridges */
-static struct pci_operations pci_bus_ops_pci = {
-	.set_subsystem = 0,
-};
-
 struct device_operations default_pci_ops_bus = {
 	.read_resources   = pci_bus_read_resources,
 	.set_resources    = pci_dev_set_resources,
 	.enable_resources = pci_bus_enable_resources,
 	.scan_bus         = pci_scan_bridge,
 	.reset_bus        = pci_bus_reset,
-	.ops_pci          = &pci_bus_ops_pci,
 };
 
 /**