!1617 LoonArch: KVM: fix vcpu timer

Merge Pull Request from: @ddjsaiwqq 
 
Fix vcpu timer initialize, saved, restore and triggered functions.
As the previous code does not init vcpu timer, and the timer value
should add time value instead of ticks value to calculate the expire 
time when vcpu timer triggered.
 
 
Link:https://gitee.com/openeuler/kernel/pulls/1617

 

Reviewed-by: Kevin Zhu <zhukeqian1@huawei.com>
Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com>