sb/intel: Clean up some SMI enables

Change-Id: I191ad709fd3c6f906cd34b0053eeaebdb80d410d
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/42354
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/Kconfig

@@ -829,6 +829,10 @@ config DEBUG_SMI
 
 	  If unsure, say N.
 
+config DEBUG_PERIODIC_SMI
+	bool "Trigger SMI periodically"
+	depends on DEBUG_SMI
+
 # Only visible if debug level is DEBUG (7) or SPEW (8) as it does additional
 # printk(BIOS_DEBUG, ...) calls.
 config DEBUG_MALLOC