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/activation.py

@@ -20,9 +20,9 @@ import torch
 import torch.nn as nn
 import torch.nn.functional as F
 
-from sglang.srt.utils import is_hip
+from sglang.srt.utils import is_flashinfer_available
 
-if not is_hip():
+if is_flashinfer_available():
     from flashinfer.activation import gelu_and_mul, gelu_tanh_and_mul, silu_and_mul
 
 from vllm.distributed import (
@@ -146,8 +146,8 @@ def get_act_fn(
     return act_fn
 
 
-if is_hip():
+if not is_flashinfer_available():
     logger.info(
-        "FlashInfer is not available on AMD GPUs. Fallback to other kernel libraries."
+        "FlashInfer is not available on Non-NV GPUs. Fallback to other kernel libraries."
     )
     from vllm.model_executor.layers.activation import GeluAndMul, SiluAndMul