device/device.h: Rename busses for clarity

This renames bus to upstream and link_list to downstream.

Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Change-Id: I80a81b6b8606e450ff180add9439481ec28c2420
Reviewed-on: https://review.coreboot.org/c/coreboot/+/78330
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
diff --git a/src/soc/intel/xeon_sp/uncore_acpi.c b/src/soc/intel/xeon_sp/uncore_acpi.c
index e2b47329..75b281b 100644
--- a/src/soc/intel/xeon_sp/uncore_acpi.c
+++ b/src/soc/intel/xeon_sp/uncore_acpi.c
@@ -225,7 +225,7 @@
 							 uint32_t pcie_seg,
 							 bool is_atsr, bool *first)
 {
-	const uint32_t bus = bridge_dev->bus->secondary;
+	const uint32_t bus = bridge_dev->upstream->secondary;
 	const uint32_t dev = PCI_SLOT(bridge_dev->path.pci.devfn);
 	const uint32_t func = PCI_FUNC(bridge_dev->path.pci.devfn);