[1/N][Attention] Restructure attention: move files (#31916)

Signed-off-by: Matthew Bonanni <mbonanni@redhat.com>

vllm/model_executor/models/seed_oss.py

@@ -30,7 +30,6 @@ import torch
 from torch import nn
 from transformers import PretrainedConfig as SeedOssConfig
 
-from vllm.attention.backends.abstract import AttentionType
 from vllm.attention.layer import Attention
 from vllm.compilation.decorators import support_torch_compile
 from vllm.config import CacheConfig, VllmConfig
@@ -56,6 +55,7 @@ from vllm.model_executor.model_loader.weight_utils import (
 )
 from vllm.sequence import IntermediateTensors
 from vllm.transformers_utils.config import set_default_rope_theta
+from vllm.v1.attention.backend import AttentionType
 
 from .interfaces import SupportsLoRA, SupportsPP
 from .utils import (