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/arch/x86/mpspec.c b/src/arch/x86/mpspec.c
index 3ddee2f..b8bdb09 100644
--- a/src/arch/x86/mpspec.c
+++ b/src/arch/x86/mpspec.c
@@ -284,11 +284,11 @@
 
 	unsigned char dstirq_x[4];
 
-	if (!dev->link_list)
+	if (!dev->downstream)
 		return;
 
-	child = dev->link_list->children;
-	srcbus = dev->link_list->secondary;
+	child = dev->downstream->children;
+	srcbus = dev->downstream->secondary;
 
 	while (child) {
 		if (child->path.type != DEVICE_PATH_PCI)
@@ -476,7 +476,7 @@
 	memset(buses, 0, sizeof(buses));
 
 	for (dev = all_devices; dev; dev = dev->next) {
-		struct bus *bus = dev->link_list;
+		struct bus *bus = dev->downstream;
 		if (!bus)
 			continue;
 		if (bus->secondary > 255) {