!4292 powerpc: Add PVN support for HeXin C2000 processor

Merge Pull Request from: @byterzj 
 
HeXin Tech Co. has applied for a new PVN from the OpenPower Community
for its new processor C2000. The OpenPower has assigned a new PVN
and this newly assigned PVN is 0x0066, add pvr register related
support for this PVN.

https://gitee.com/openeuler/kernel/issues/I8ZMAY

This patch include:
backport PVN form mainline

Test:
no functional modifications involved 
 
Link:https://gitee.com/openeuler/kernel/pulls/4292

 

Reviewed-by: Zhang Jianhua <chris.zjh@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>