fix: fix sw64 CPU driver incompatible function pointer

Remove extra virCPUFeaturePolicy parameter from virCPUsw64Update
to match the virCPUArchUpdate typedef which expects 3 parameters.
This caused -Werror=incompatible-pointer-types build failure on loong64.

Log: Fixed sw64 CPU driver function signature mismatch

Influence:
1. Verify libvirt builds successfully on loong64/sw64 architectures
2. Verify sw64 CPU driver update function works correctly
3. Ensure no regression on other architectures

fix: 修复 sw64 CPU 驱动函数指针不兼容

删除 virCPUsw64Update 多余的 virCPUFeaturePolicy 参数
匹配 virCPUArchUpdate 类型定义期望的 3 个参数

Log: 修复 sw64 CPU 驱动函数签名不匹配

Influence:
1. 验证 loong64/sw64 架构上 libvirt 构建成功
2. 验证 sw64 CPU 驱动更新函数正常工作
3. 确保其他架构无回归

repo: libvirt #master
