[Feat] Add mrope fusion op (#3708)

### What this PR does / why we need it?
Add mrope fusion op for qwen2.5-vl. This mrope operator dosen't support
Qwen3-VL currently. Thus could only take affect in qwen2.5-vl

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

Signed-off-by: shaopeng666 <shaopeng666@noreply.gitcode.com>
Co-authored-by: shaopeng666 <shaopeng666@noreply.gitcode.com>

vllm_ascend/ops/rotary_embedding.py

@@ -22,7 +22,7 @@ import torch
 import torch_npu
 from vllm.forward_context import get_forward_context
 from vllm.model_executor.layers.rotary_embedding import (
-    DeepseekScalingRotaryEmbedding, RotaryEmbedding,
+    DeepseekScalingRotaryEmbedding, MRotaryEmbedding, RotaryEmbedding,
     YaRNScalingRotaryEmbedding)
 
 from vllm_ascend.platform import NPUPlatform
@@ -395,3 +395,37 @@ class AscendDeepseekScalingRotaryEmbedding(DeepseekScalingRotaryEmbedding):
         q_pe, k_pe = _rope_forward_oot(self, positions, query, key,
                                        is_neox_style, offsets)
         return q_pe, k_pe
+
+
+class AscendMRotaryEmbedding(MRotaryEmbedding):
+
+    def forward_oot(
+        self,
+        positions: torch.Tensor,
+        query: torch.Tensor,
+        key: torch.Tensor,
+    ):
+        if self.mrope_section != [16, 24, 24]:
+            return super().forward_oot(positions, query, key)
+
+        import torch_npu
+        mrope_section = [0, 0, 0
+                         ] if positions.ndim == 1 else self.mrope_section
+
+        if self.cos_sin_cache.device != query.device:  # type: ignore
+            self.cos_sin_cache = self.cos_sin_cache.to(  # type: ignore
+                query.device)  # type: ignore
+
+        if self.cos_sin_cache.dtype != query.dtype:  # type: ignore
+            self.cos_sin_cache = self.cos_sin_cache.to(  # type: ignore
+                query.dtype)  # type: ignore
+
+        query, key = torch_npu.npu_mrope(positions,
+                                         query.contiguous(),
+                                         key.contiguous(),
+                                         self.cos_sin_cache.contiguous(),
+                                         self.head_size,
+                                         mrope_section=mrope_section,
+                                         rotary_mode='half')
+
+        return query, key