AGESA: Use pcidev_on_root()

We have constant CONFIG_CBB==0, replace ill dev_find_slot()
with safe pcidev_on_root();

Change-Id: Ieb2030fa3d77a9f49fc5faf12b92b5f00f49d354
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/26482
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/southbridge/amd/agesa/hudson/sd.c b/src/southbridge/amd/agesa/hudson/sd.c
index e98be57..878f136 100644
--- a/src/southbridge/amd/agesa/hudson/sd.c
+++ b/src/southbridge/amd/agesa/hudson/sd.c
@@ -25,7 +25,7 @@
 {
 	u32 stepping;
 
-	stepping = pci_read_config32(dev_find_slot(0, PCI_DEVFN(0x18, 3)), 0xFC);
+	stepping = pci_read_config32(pcidev_on_root(0x18, 3), 0xFC);
 
 	struct southbridge_amd_agesa_hudson_config *sd_chip =
 		(struct southbridge_amd_agesa_hudson_config *)(dev->chip_info);