[bugfix] fix NaN lse of _correct_attn_cp_out_kernel

Signed-off-by: QiuChunshuo <qiuchunshuo@huawei.com>

Author: pisceskkk

vllm/attention/ops/common.py

@@ -53,6 +53,7 @@ def _correct_attn_cp_out_kernel(
  lse = tl.load(lses_ptr + lse_offsets)
  lse = tl.where((lse != lse) | (lse == float("inf")), -float("inf"), lse)
  lse_max = tl.max(lse, axis=0)
+ lse_max = tl.where(lse_max == -float("inf"), 0, lse_max)
  lse -= lse_max
  lse_exp = tl.exp(lse)
  lse_acc = tl.sum(lse_exp, axis=0)