arch/x86: Avoid HAVE_SMI_HANDLER conditional with smm-class

Build of the entire smm-class is skipped if we have
HAVE_SMI_HANDLER=n.

Change-Id: I10b4300ddd18b1673c404b45fd9642488ab3186c
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34125
Reviewed-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Furquan Shaikh <furquan@google.com>
Reviewed-by: Lance Zhao <lance.zhao@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/cpu/intel/model_206ax/Makefile.inc b/src/cpu/intel/model_206ax/Makefile.inc
index 78a6283..f5de8c3 100644
--- a/src/cpu/intel/model_206ax/Makefile.inc
+++ b/src/cpu/intel/model_206ax/Makefile.inc
@@ -15,14 +15,14 @@
 
 ramstage-y += common.c
 romstage-y += common.c
-smm-$(CONFIG_HAVE_SMI_HANDLER) += common.c
+smm-y += common.c
 
 ramstage-y += tsc_freq.c
 romstage-y += tsc_freq.c
 postcar-y += tsc_freq.c
-smm-$(CONFIG_HAVE_SMI_HANDLER) += tsc_freq.c
+smm-y += tsc_freq.c
 
-smm-$(CONFIG_HAVE_SMI_HANDLER) += finalize.c
+smm-y += finalize.c
 
 romstage-$(CONFIG_CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM) += stage_cache.c
 postcar-$(CONFIG_CACHE_RELOCATED_RAMSTAGE_OUTSIDE_CBMEM) += stage_cache.c