superio/ite/it8721f: Trivial drop redundant headers

Change-Id: Ib086cd567c926dd659f67900195f93262ceb50c3
Signed-off-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
Reviewed-on: http://review.coreboot.org/5839
Tested-by: build bot (Jenkins)
Reviewed-by: Idwer Vollering <vidwer@gmail.com>