### What this PR does / why we need it?
In mooncake kvpool, `local_hostname` is not used. Instead, the local IP
is obtained directly via `get_ip()`. Therefore, remove this parameter to
avoid confusion.
### How was this patch tested?
- vLLM version: v0.13.0
- vLLM main:
7157596103
Signed-off-by: LCAIZJ <leichao139636@163.com>