coreboot: Replace all IS_ENABLED(CONFIG_XXX) with CONFIG(XXX)

This patch is a raw application of

 find src/ -type f | xargs sed -i -e 's/IS_ENABLED\s*(CONFIG_/CONFIG(/g'

Change-Id: I6262d6d5c23cabe23c242b4f38d446b74fe16b88
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31774
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>

src/include/cper.h

@@ -386,7 +386,7 @@ typedef struct cper_ia32x64_ctx_x64state {
 static inline cper_timestamp_t cper_timestamp(int precise)
 {
 	cper_timestamp_t ts;
-#if IS_ENABLED(CONFIG_RTC)
+#if CONFIG(RTC)
 	struct rtc_time time;
 
 	rtc_get(&time);