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/device/oprom/realmode/x86.c b/src/device/oprom/realmode/x86.c
index 367614d..c3adf40 100644
--- a/src/device/oprom/realmode/x86.c
+++ b/src/device/oprom/realmode/x86.c
@@ -415,7 +415,7 @@
 
 void run_bios(struct device *dev, unsigned long addr)
 {
-	u32 num_dev = (dev->bus->secondary << 8) | dev->path.pci.devfn;
+	u32 num_dev = (dev->upstream->secondary << 8) | dev->path.pci.devfn;
 
 	/* Setting up required hardware.
 	 * Removing this will cause random illegal instruction exceptions