cpu/intel/model_206ax: Clean up includes

Change-Id: I5dc2e7b327278c281087c7461e62569aab3fe450
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43692
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>

src/cpu/intel/model_206ax/finalize.c

@@ -2,7 +2,6 @@
 
 #include <arch/cpu.h>
 #include <cpu/x86/msr.h>
-#include <cpu/intel/speedstep.h>
 #include "model_206ax.h"
 
 /* MSR Documentation based on