southbridge/intel: add IS_ENABLED() around Kconfig symbol references

Change-Id: I2b532522938123bb7844cef94cda0b44bcb98e45
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20350
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
diff --git a/src/southbridge/intel/ibexpeak/lpc.c b/src/southbridge/intel/ibexpeak/lpc.c
index f01d8b2..a152dfe 100644
--- a/src/southbridge/intel/ibexpeak/lpc.c
+++ b/src/southbridge/intel/ibexpeak/lpc.c
@@ -71,7 +71,7 @@
 	/* Set packet length and toggle silent mode bit for one frame. */
 	pci_write_config8(dev, SERIRQ_CNTL,
 			  (1 << 7) | (1 << 6) | ((21 - 17) << 2) | (0 << 0));
-#if !CONFIG_SERIRQ_CONTINUOUS_MODE
+#if !IS_ENABLED(CONFIG_SERIRQ_CONTINUOUS_MODE)
 	pci_write_config8(dev, SERIRQ_CNTL,
 			  (1 << 7) | (0 << 6) | ((21 - 17) << 2) | (0 << 0));
 #endif
@@ -280,7 +280,7 @@
 	if (rtc_failed) {
 		reg8 &= ~RTC_BATTERY_DEAD;
 		pci_write_config8(dev, GEN_PMCON_3, reg8);
-#if CONFIG_ELOG
+#if IS_ENABLED(CONFIG_ELOG)
 		elog_add_event(ELOG_TYPE_RTC_RESET);
 #endif
 	}