soc/intel: Replace uses of dev_find_slot()

To call dev_find_slot(0, xx) in romstage can produce
invalid results since PCI bus enumeration has not
been progressed yet.

Replace this with method that relies on bus topology
that walks the root bus only.

Change-Id: I2883610059bb9fa860bba01179e7d5c58cae00e5
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/33996
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/soc/intel/skylake/pmutil.c

@@ -178,7 +178,7 @@ void soc_get_gpi_gpe_configs(uint8_t *dw0, uint8_t *dw1, uint8_t *dw2)
 	DEVTREE_CONST struct soc_intel_skylake_config *config;
 
 	/* Look up the device in devicetree */
-	DEVTREE_CONST struct device *dev = dev_find_slot(0, PCH_DEVFN_PMC);
+	DEVTREE_CONST struct device *dev = pcidev_path_on_root(PCH_DEVFN_PMC);
 	if (!dev || !dev->chip_info) {
 		printk(BIOS_ERR, "BUG! Could not find SOC devicetree config\n");
 		return;