Function round_up

dnn/src/common/utils.h:417–422

 */
template <typename int_t>
int_t round_up(int_t dividend, int_t divisor) {
    static_assert(std::is_integral<int_t>::value, "must be integers");
    megdnn_assert_internal(dividend >= 0);
    megdnn_assert_internal(divisor > 0);
    return ((dividend + divisor - 1) / divisor) * divisor;
}

template <typename T, typename S, typename Func>
SmallVector<T> apply_vector(Func&& func, const SmallVector<S>& vec) {