KVM: Enable PUD huge mappings only on 1620

virt inclusion
category: bugfix
bugzilla: 47428
CVE: NA

Disable PUD_SIZE huge mapping on 161x serial boards and only
enable on 1620CS due to low performance on cache maintenance
and complex implementation for pre-setup stage2 page table with
PUD huge page. Which would even lead to hard lockup

Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: miaoyubo <miaoyubo@huawei.com>
Reviewed-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Cheng Jian <cj.chengjian@huawei.com>