[Bugfix] Store Qwen3Next A_log in fp32 (#37810)

Signed-off-by: effortprogrammer <yhjhoward7@gmail.com>
Co-authored-by: Roger Wang <hey@rogerw.io>

vllm/model_executor/models/qwen3_next.py

@@ -501,6 +501,7 @@ class Qwen3NextGatedDeltaNet(nn.Module, MambaBase):
         self.A_log = nn.Parameter(
             torch.empty(
                 divide(self.num_v_heads, self.tp_size),
+                dtype=torch.float32,
             )
         )