cpu/x86: Separate save_state struct headers

Any platform should need just one of these.

Change-Id: Ia0ff8eff152cbd3d82e8b372ec662d3737078d35
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34820
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/apollolake/cpu.c

@@ -30,6 +30,7 @@
 #include <cpu/x86/msr.h>
 #include <cpu/x86/mtrr.h>
 #include <cpu/x86/smm.h>
+#include <cpu/intel/em64t100_save_state.h>
 #include <device/device.h>
 #include <device/pci.h>
 #include <fsp/api.h>