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

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

vllm/model_executor/layers/fused_moe/layer.py

@@ -1593,7 +1593,7 @@ class FusedMoE(CustomOp):
         else:
             return tensor_model_parallel_all_reduce(final_hidden_states)
 
-    def forward(
+    def forward_native(
         self,
         hidden_states: torch.Tensor,
         router_logits: torch.Tensor,
@@ -1627,6 +1627,13 @@ class FusedMoE(CustomOp):
             return (shared_output[..., :og_hidden_states],
                     fused_output[..., :og_hidden_states])
 
+    def forward_cuda(
+        self,
+        hidden_states: torch.Tensor,
+        router_logits: torch.Tensor,
+    ) -> Union[torch.Tensor, tuple[torch.Tensor, torch.Tensor]]:
+        return self.forward_native(hidden_states, router_logits)
+
     def forward_impl_chunked(
         self,
         full_hidden_states: torch.Tensor,