Merge Pull Request from: @guzitao 
 
These patches generally cover the following tasks:

1.optimize kernel cores, remove unused codes, fix compile errors
2.fixes for perf, iommu
3.add support, add CONFIG_THREAD_INFO_IN_TASK support, support SIMD IO access in guest, add DVFS support 
 
Link:https://gitee.com/openeuler/kernel/pulls/425 

Reviewed-by: Zheng Zengkai <zhengzengkai@huawei.com> 
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>