remove redundant params in mla_preprocess kernel (#3530)

### What this PR does / why we need it?

This pull request removes the redundant parameters `gamma1` and `beta1`
(also named `gamma0`/`beta0` in some places) from the `mla_preprocess`
kernel and its calling hierarchy. The changes are consistent across C++
kernel code, bindings, and Python call sites. The parameters were unused
in the lower-level functions, so their removal is a good cleanup.

### Does this PR introduce _any_ user-facing change?

The python interface of the kernel is affected, and the params of
`gamma0` and `beta0` are not needed.

### How was this patch tested?

The unit-test of the kernel is adapted accordingly.


- vLLM version: v0.11.0rc3
- vLLM main: https://github.com/vllm-project/vllm/commit/v0.11.0

Signed-off-by: mojave2 <chenchen145@huawei.com>

csrc/torch_binding_meta.cpp

@@ -83,8 +83,6 @@ at::Tensor sgmv_expand_meta(at::Tensor &x, at::Tensor &weight, at::Tensor &lora_
 
 std::tuple<at::Tensor &, at::Tensor &, at::Tensor &, at::Tensor &> mla_preprocess(
     const at::Tensor &hiddenState,
-    const at::Tensor &gamma0,
-    const at::Tensor &beta0,
     const at::Tensor &wdqkv,
     const at::Tensor &descale0,
     const at::Tensor &gamma1,