src: Fix the warning "type 'hex' are always defined"

This is spotted using "./util/lint/kconfig_lint"
While at it, do the check in C and not the preprocessor.

Change-Id: Icfda267936a23d9d14832116d67571f42f685906
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/31050
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Nico Huber <nico.h@gmx.de>
diff --git a/src/soc/intel/skylake/chip_fsp20.c b/src/soc/intel/skylake/chip_fsp20.c
index 18c2aef..3ade8d7 100644
--- a/src/soc/intel/skylake/chip_fsp20.c
+++ b/src/soc/intel/skylake/chip_fsp20.c
@@ -391,14 +391,16 @@
 		params->SpiFlashCfgLockDown = 0;
 	}
 	/* only replacing preexisting subsys ID defaults when non-zero */
-#if defined(CONFIG_SUBSYSTEM_VENDOR_ID) && CONFIG_SUBSYSTEM_VENDOR_ID
-	params->DefaultSvid = CONFIG_SUBSYSTEM_VENDOR_ID;
-	params->PchSubSystemVendorId = CONFIG_SUBSYSTEM_VENDOR_ID;
-#endif
-#if defined(CONFIG_SUBSYSTEM_DEVICE_ID) && CONFIG_SUBSYSTEM_DEVICE_ID
-	params->DefaultSid = CONFIG_SUBSYSTEM_DEVICE_ID;
-	params->PchSubSystemId = CONFIG_SUBSYSTEM_DEVICE_ID;
-#endif
+	if (CONFIG_SUBSYSTEM_VENDOR_ID != 0) {
+		params->DefaultSvid = CONFIG_SUBSYSTEM_VENDOR_ID;
+		params->PchSubSystemVendorId = CONFIG_SUBSYSTEM_VENDOR_ID;
+	}
+
+	if (CONFIG_SUBSYSTEM_DEVICE_ID != 0) {
+		params->DefaultSid = CONFIG_SUBSYSTEM_DEVICE_ID;
+		params->PchSubSystemId = CONFIG_SUBSYSTEM_DEVICE_ID;
+	}
+
 	params->PchPmWolEnableOverride = config->WakeConfigWolEnableOverride;
 	params->PchPmPcieWakeFromDeepSx = config->WakeConfigPcieWakeFromDeepSx;
 	params->PchPmDeepSxPol = config->PmConfigDeepSxPol;