[platforms] enable platform plugins (#11602)

Signed-off-by: youkaichao <youkaichao@gmail.com>

vllm/model_executor/models/registry.py

@@ -18,7 +18,6 @@ import cloudpickle
 import torch.nn as nn
 
 from vllm.logger import init_logger
-from vllm.platforms import current_platform
 
 from .interfaces import (has_inner_state, is_attention_free, is_hybrid,
                          supports_cross_encoding, supports_multimodal,
@@ -273,6 +272,7 @@ def _try_load_model_cls(
     model_arch: str,
     model: _BaseRegisteredModel,
 ) -> Optional[Type[nn.Module]]:
+    from vllm.platforms import current_platform
     current_platform.verify_model_arch(model_arch)
     try:
         return model.load_model_cls()