[feat] mlapo add bf16 no_quant support (#4852)

### What this PR does / why we need it?
This PR adds mlapo operation support for bf16 no_quant mode.

### Does this PR introduce _any_ user-facing change?
This PR makes quant related parameters optional. 
### How was this patch tested?
CI passed with new added/existing test.

- vLLM version: v0.12.0
- vLLM main:
ad32e3e19c

---------

Signed-off-by: chenjunyi <isjunyi.chen@gmail.com>

tests/e2e/nightly/ops/test_mla_preprocess.py

@@ -67,6 +67,11 @@ def test_mla_preprocess_kernel():
         dtype=hidden_states.dtype,
         device=hidden_states.device,
     )
+    q_down = torch.empty(
+        (hidden_states.shape[0], 1536),
+        dtype=hidden_states.dtype,
+        device=hidden_states.device,
+    )
     q_nope_old = q_nope_out.clone()
     q_rope_old = q_rope_out.clone()
 
@@ -95,10 +100,12 @@ def test_mla_preprocess_kernel():
         q_nope_scale=qnope_scale,
         cache_mode="krope_ctkv",
         quant_mode="per_tensor_quant_asymm",
+        enable_inner_out=False,
         q_out0=q_nope_out,
         kv_cache_out0=kv_cache,
         q_out1=q_rope_out,
         kv_cache_out1=kv_cache_rope,
+        inner_out=q_down,
     )
     assert not torch.equal(q_nope_out, q_nope_old)
     assert not torch.equal(q_rope_out, q_rope_old)