MIPS: cacheinfo: Add missing VCache

Victim Cache is defined by Loongson as per-core unified
private Cache.
Add this into cacheinfo and make cache levels selfincrement
instead of hardcode levels.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Reviewed-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Tested-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>