soc/intel/apollolake: Make use of is_devfn_enabled() function

1. Replace all pcidev_path_on_root() and is_dev_enabled() functions
combination with is_devfn_enabled().
2. Remove unused local variable of device structure type
(struct device *).
3. Replace pcidev_path_on_root() and dev->enabled check with
is_devfn_enabled() call.

TEST=Able to build and boot without any regression seen on Reef.

Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Change-Id: I900038dd4b2e2d89b1236bbd26bec5f34483b9f3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/55327
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/src/soc/intel/apollolake/chip.c b/src/soc/intel/apollolake/chip.c
index 7172231..9694c67 100644
--- a/src/soc/intel/apollolake/chip.c
+++ b/src/soc/intel/apollolake/chip.c
@@ -533,7 +533,6 @@
 {
 #if CONFIG(SOC_INTEL_GEMINILAKE)
 	uint8_t port;
-	struct device *dev;
 
 	for (port = 0; port < APOLLOLAKE_USB2_PORT_MAX; port++) {
 		if (!cfg->usb2eye[port].Usb20OverrideEn)
@@ -549,8 +548,7 @@
 			cfg->usb2eye[port].Usb20IUsbTxEmphasisEn;
 	}
 
-	dev = pcidev_path_on_root(SA_GLK_DEVFN_GMM);
-	silconfig->Gmm = is_dev_enabled(dev);
+	silconfig->Gmm = is_devfn_enabled(SA_GLK_DEVFN_GMM);
 
 	/* On Geminilake, we need to override the default FSP PCIe de-emphasis
 	 * settings using the device tree settings. This is because PCIe
@@ -693,8 +691,7 @@
 	/* Set VTD feature according to devicetree */
 	silconfig->VtdEnable = cfg->enable_vtd;
 
-	dev = pcidev_path_on_root(SA_DEVFN_IGD);
-	silconfig->PeiGraphicsPeimInit = CONFIG(RUN_FSP_GOP) && is_dev_enabled(dev);
+	silconfig->PeiGraphicsPeimInit = CONFIG(RUN_FSP_GOP) && is_devfn_enabled(SA_DEVFN_IGD);
 
 	silconfig->PavpEnable = CONFIG(PAVP);