sb/amd/cs5536: Remove unneeded include <cpu/x86/bist.h>

Change-Id: Ifae9d67bbba57b30ee9a2f31c448efcb27981c57
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/29310
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Marshall Dawson <marshalldawson3rd@gmail.com>

src/southbridge/amd/cs5536/early_setup.c

@@ -20,7 +20,6 @@
  */
 
 #include <arch/io.h>
-#include <cpu/x86/bist.h>
 #include <cpu/x86/msr.h>
 #include <cpu/amd/lxdef.h>
 #include "cs5536.h"