[Bugfix] Fix platform-specific routing in CustomOp implementations (#24444)

Signed-off-by: Konrad Zawora <kzawora@habana.ai>

vllm/model_executor/layers/activation.py

@@ -454,7 +454,7 @@ class XIELU(CustomOp):
         )
         return result.view(original_shape)
 
-    def forward(self, input: torch.Tensor) -> torch.Tensor:
+    def forward_native(self, input: torch.Tensor) -> torch.Tensor:
         if self._xielu_cuda_obj is not None and input.is_cuda:
             if not torch._dynamo.is_compiling():
                 return self._xielu_cuda_fn(input)
@@ -464,6 +464,9 @@ class XIELU(CustomOp):
                 )
         return self._xielu_python(input)
 
+    def forward_cuda(self, input: torch.Tensor) -> torch.Tensor:
+        return self.forward_native(input)
+
 
 class ScaledActivation(nn.Module):
     """An activation function with post-scale parameters.