BSND to TND and FA_UPDATE replacement

Signed-off-by: pichangping <[email protected]>

Author: pichangping

vllm_ascend/attention/attention_v1.py

@@ -23,7 +23,6 @@
 import torch
 import torch.distributed as dist
 import torch.nn as nn
-import torch.nn.functional as F
 import torch_npu
 from vllm.attention.backends.abstract import (AttentionBackend, AttentionImpl,
                                               AttentionLayer, AttentionType)