Combine fp4.py and mxfp4.py into one file and support dynamic mxfp4 quantization in mxfp4.py (#9049)

Co-authored-by: wunhuang <wunhuang@amd.com>

python/sglang/srt/server_args.py

@@ -33,6 +33,7 @@ from sglang.srt.utils import (
     configure_ipv6,
     get_device,
     get_device_memory_capacity,
+    is_cuda,
     is_flashinfer_available,
     is_hip,
     is_port_available,
@@ -2165,9 +2166,9 @@ class ServerArgs:
         model_arch = hf_config.architectures[0]
         if model_arch in ["GptOssForCausalLM"]:
             if self.attention_backend is None:
-                if is_sm100_supported():
+                if is_cuda() and is_sm100_supported():
                     self.attention_backend = "trtllm_mha"
-                elif is_sm90_supported():
+                elif is_cuda() and is_sm90_supported():
                     self.attention_backend = "fa3"
                 else:
                     self.attention_backend = "triton"