src/mainboard/*/*/cstates.c: Drop unused includes

Change-Id: I315721d6261e558c3f7145c80714262052ce0e49
Signed-off-by: Elyes HAOUAS <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31783
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/getac/p470/cstates.c

@@ -11,7 +11,6 @@
  * GNU General Public License for more details.
  */
 
-#include <device/device.h>
 #include <arch/acpigen.h>
 #include <southbridge/intel/i82801gx/i82801gx.h>