soc/intel/alderlake: Use devfn_disable() function for XDCI

Use devfn_disable() for disabling a PCI device rather than
using `dev->enabled = 0`.

Also, use is_devfn_enabled() to get the device current state prior
updating the FSP-S UPD for XDCI.

TEST=FSP-S disabled XDCI when `xdci_can_enable` returns 0 and XDCI
is disabled at PCI enumeration `PCI: 00:14.1: enabled 0`.

Change-Id: I5e10e5d0b80986e1e73573a86a957985840fe0b3
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55727
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/intel/alderlake/fsp_params.c b/src/soc/intel/alderlake/fsp_params.c
index 0170eec..0987b41 100644
--- a/src/soc/intel/alderlake/fsp_params.c
+++ b/src/soc/intel/alderlake/fsp_params.c
@@ -82,7 +82,6 @@
 	FSPS_ARCH_UPD *pfsps_arch_upd = &supd->FspsArchUpd;
 	uint32_t enable_mask;
 
-	struct device *dev;
 	struct soc_intel_alderlake_config *config;
 	config = config_of_soc();
 	mainboard_update_soc_chip_config(config);
@@ -179,14 +178,9 @@
 	pfsps_arch_upd->EnableMultiPhaseSiliconInit = 1;
 
 	/* Enable xDCI controller if enabled in devicetree and allowed */
-	dev = pcidev_path_on_root(PCH_DEVFN_USBOTG);
-	if (dev) {
-		if (!xdci_can_enable())
-			dev->enabled = 0;
-		params->XdciEnable = dev->enabled;
-	} else {
-		params->XdciEnable = 0;
-	}
+	if (!xdci_can_enable())
+		devfn_disable(pci_root_bus(), PCH_DEVFN_USBOTG);
+	params->XdciEnable = is_devfn_enabled(PCH_DEVFN_USBOTG);
 
 	/* PCH UART selection for FSP Debug */
 	params->SerialIoDebugUartNumber = CONFIG_UART_FOR_CONSOLE;