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/soc/intel/skylake/cpu.c

@@ -489,7 +489,7 @@ static void post_mp_init(void)
 	smm_southbridge_enable(GBL_EN);
 
 	/* Lock down the SMRAM space. */
-#if IS_ENABLED(CONFIG_HAVE_SMI_HANDLER)
+#if CONFIG(HAVE_SMI_HANDLER)
 	smm_lock();
 #endif