Fix ut mla-test-1-gpu-amd (#4813)

Co-authored-by: Zhang Kaihong <zhangkaihong.zkh@alibaba-inc.com>

python/sglang/srt/layers/rotary_embedding.py

@@ -645,6 +645,18 @@ class DeepseekScalingRotaryEmbedding(RotaryEmbedding):
         cache = torch.cat((cos, sin), dim=-1)
         return cache
 
+    def forward(
+        self,
+        positions: torch.Tensor,
+        query: torch.Tensor,
+        key: torch.Tensor,
+        offsets: Optional[torch.Tensor] = None,
+    ) -> Tuple[torch.Tensor, torch.Tensor]:
+        if _is_cuda_available:
+            return self.forward_cuda(positions, query, key, offsets)
+        else:
+            return self.forward_native(positions, query, key, offsets)
+
     def forward_native(
         self,
         positions: torch.Tensor,