security/intel/stm: Add missing <stdbool.h>

Jenkins does not build `config.stm` because the file name lacks the
mainboard name. So, the code was not being build-tested, and it does not
build because several files lacked the definition for `bool`.

Add the missing #include directives. Renaming the config file so that
Jenkins build-tests it is done in a follow-up.

Change-Id: Idf012b7ace0648027ef6e901d821ca6682cee198
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43622
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: HAOUAS Elyes <ehaouas@noos.fr>
Reviewed-by: Eugene Myers <cedarhouse1@comcast.net>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/security/intel/stm/SmmStm.c

@@ -6,6 +6,7 @@
 #include <cpu/x86/msr.h>
 #include <cpu/x86/cache.h>
 #include <security/intel/stm/SmmStm.h>
+#include <stdbool.h>
 #include <string.h>
 
 #define TXT_EVTYPE_BASE 0x400

src/security/intel/stm/SmmStm.h

@@ -4,6 +4,7 @@
 #define _SMM_STM_H_
 
 #include "StmApi.h"
+#include <stdbool.h>
 
 /*
  *  Load STM image.

src/security/intel/stm/StmPlatformSmm.c

@@ -9,6 +9,7 @@
 
 #include <cbfs.h>
 #include <console/console.h>
+#include <stdbool.h>
 #include <stdint.h>
 #include <arch/rom_segs.h>