Update to serial_protocol_spec.md
Update to serial_protocol_spec.md

removed status bytes from MI receipt
PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,scanse/sweep-sdk,PeterJohnson/sweep-sdk,PeterJohnson/sweep-sdk