[Refact.]: Refactor some leftover implementations of 300I DUO in the main branch. (#6425)

### What this PR does / why we need it?
- Replace the RoPE operator implementation.
- Refactor some leftover implementations of 300I DUO in the main branch.

### Does this PR introduce _any_ user-facing change?
NA
### How was this patch tested?

- vLLM version: v0.14.1
- vLLM main:
dc917cceb8

---------

Signed-off-by: Tflowers-0129 <2906339855@qq.com>

vllm_ascend/_310p/ops/activation.py

@@ -18,13 +18,13 @@
 import torch
 import torch.nn.functional as F
 
-from vllm_ascend.ops.activation import AscendSiluAndMul as _Base
+from vllm_ascend.ops.activation import AscendSiluAndMul
 
 
-class AscendSiluAndMul310(_Base):
+class AscendSiluAndMul310(AscendSiluAndMul):
     def forward(self, x: torch.Tensor) -> torch.Tensor:
         torch.ops.vllm.maybe_prefetch_mlp_down_proj(x)
         h = x.shape[-1] // 2
-        out = (F.silu(x[..., :h].to(torch.float32)) * x[..., h:].to(torch.float32)).to(torch.float16)
+        out = F.silu(x[..., :h]) * x[..., h:]
         torch.ops.vllm.maybe_wait_prefetch_done(out)
         return out