[linux-6.6.y] LoongArch: Update the flush cache policy

[MingcongBai]

fix when LoongArch s3 resume, Can't find image information

Ref: https://lore.kernel.org/loongarch/20240507074357.2156083-1-lijun01@kylinos.cn/

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[deepin-ci-robot]

deepin pr auto review

关键摘要:

• flush_cache_last_level 函数中硬编码的地址 CSR_DMW1_BASE 可能不适用于所有Loongson架构，需要确认是否是正确的偏移量。
• flush_cache_last_level 函数中的循环次数（cdesc->ways * 3 和 cdesc->sets）可能会导致性能问题，应该评估是否有必要进行这样的循环。
• flush_cache_last_level 函数中的 addr += 0x100000000000; 操作可能会导致地址溢出，应该检查是否有必要进行这样的操作。
• flush_cache_last_level 函数缺少对 loongson_sysconf.nr_nodes 变量的有效性检查，可能会导致未定义行为。
• flush_cache_last_level 函数缺少注释说明其用途和行为，应该添加相应的注释以提高代码的可读性。

是否建议立即修改: 是

[MingcongBai]

Tested good on a Lemote 3A6000 board.