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/mainboard/siemens/mc_apl1/variants/mc_apl5/mainboard.c b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/mainboard.c
index 8eedce6..eda4b1b 100644
--- a/src/mainboard/siemens/mc_apl1/variants/mc_apl5/mainboard.c
+++ b/src/mainboard/siemens/mc_apl1/variants/mc_apl5/mainboard.c
@@ -51,7 +51,7 @@
 
 		/* Disable clock outputs 0-3 (CLKOUT) for upstream XIO2001 PCIe to PCI
 		   Bridge. */
-		struct device *parent = dev->bus->dev;
+		struct device *parent = dev->upstream->dev;
 		if (parent && parent->device == PCI_DID_TI_XIO2001)
 			pci_write_config8(parent, 0xd8, 0x0f);
 	}
@@ -60,7 +60,7 @@
 	   mainboard. */
 	dev = dev_find_device(PCI_VID_SIEMENS, 0x403f, 0);
 	if (dev) {
-		struct device *parent = dev->bus->dev;
+		struct device *parent = dev->upstream->dev;
 		if (parent && parent->device == PCI_DID_TI_XIO2001)
 			pci_write_config8(parent, 0xd8, 0x3e);
 	}