### What this PR does / why we need it?
Fix a bug for PD disaggregate of PCP/DCP, some conditions only consider
MLA while ignoring DSA.
### Does this PR introduce _any_ user-facing change?
No
### How was this patch tested?
- vLLM version: v0.15.0
- vLLM main:
15d76f74e2
- vLLM Ascend main: 81fb7d5779
Signed-off-by: tongyuzhou <tongyuzhou1@huawei.com>
Co-authored-by: tongyuzhou <tongyuzhou1@huawei.com>