Use is_flashinfer_available to replace is_hip for flashinfer check (#1596)

Co-authored-by: Zhang Liangang <liangang.zhang@intel.com>

python/sglang/srt/layers/sampler.py

@@ -7,10 +7,9 @@ from torch import nn
 from sglang.srt.layers.logits_processor import LogitsProcessorOutput
 from sglang.srt.managers.schedule_batch import global_server_args_dict
 from sglang.srt.sampling.sampling_batch_info import SamplingBatchInfo
-from sglang.srt.utils import is_hip
+from sglang.srt.utils import is_flashinfer_available
 
-# ROCm: flashinfer available later
-if not is_hip():
+if is_flashinfer_available():
     from flashinfer.sampling import (
         min_p_sampling_from_probs,
         top_k_renorm_prob,