Merge cpu/intel/acpi.h into cpu/intel/speedstep.h

We had only some MSR definitions in there, which are used in speedstep
related code. I think speedstep.h is the better and less confusing place
for these.

Change-Id: I1eddea72c1e2d3b2f651468b08b3c6f88b713149
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: http://review.coreboot.org/1655
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/cpu/intel/speedstep/acpi.c

@@ -25,7 +25,6 @@
 #include <arch/acpigen.h>
 #include <arch/cpu.h>
 #include <cpu/x86/msr.h>
-#include <cpu/intel/acpi.h>
 #include <cpu/intel/speedstep.h>
 #include <device/device.h>