mainboard/[a-e]: add IS_ENABLED() around Kconfig symbol references

Change-Id: Icca8bac5e67f83dfc5a8f5ef1cb87c6432e0a236
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20342
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/mainboard/amd/bettong/BiosCallOuts.c

@@ -83,7 +83,7 @@ AGESA_STATUS Fch_Oem_config(UINT32 Func, UINTN FchData, VOID *ConfigPtr)
 #endif
 
 		/* XHCI configuration */
-#if CONFIG_HUDSON_XHCI_ENABLE
+#if IS_ENABLED(CONFIG_HUDSON_XHCI_ENABLE)
 		FchParams_env->Usb.Xhci0Enable = TRUE;
 #else
 		FchParams_env->Usb.Xhci0Enable = FALSE;