soc/amd/cezanne: add empty SMM-handler

Signed-off-by: Felix Held <felix-coreboot@felixheld.de>
Change-Id: I95908fac3b1e17a16542e5d80001fac3d22d839a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/50455
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/cezanne/smihandler.c b/src/soc/amd/cezanne/smihandler.c
new file mode 100644
index 0000000..2d9e487
--- /dev/null
+++ b/src/soc/amd/cezanne/smihandler.c
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <cpu/x86/smm.h>
+
+void southbridge_smi_handler(void)
+{
+}