Revert "Support aiter RMSNorm in AMD (sgl-project#5510)"

This reverts commit 968ef51.

Author: michael-amd

python/sglang/srt/layers/layernorm.py

@@ -20,12 +20,9 @@
 import torch.nn as nn
 
 from sglang.srt.custom_op import CustomOp
-from sglang.srt.utils import is_cuda, is_hip
-
-logger = logging.getLogger(__name__)
+from sglang.srt.utils import is_cuda
 
 _is_cuda = is_cuda()
-_is_hip = is_hip()
 
 if _is_cuda:
     from sgl_kernel import (
@@ -35,20 +32,8 @@
         rmsnorm,
     )
 
-if _is_hip:
-
-    from aiter.ops.rmsnorm import rms_norm, rmsnorm2d_fwd_with_add
 
-    rmsnorm = rms_norm
-
-    def fused_add_rmsnorm(
-        x: torch.Tensor,
-        residual: torch.Tensor,
-        w: torch.Tensor,
-        eps: float,
-    ) -> Tuple[torch.Tensor, torch.Tensor]:
-        rmsnorm2d_fwd_with_add(x, x, residual, residual, w, eps)
-        return x, residual
+logger = logging.getLogger(__name__)
 
 
 class RMSNorm(CustomOp):
@@ -154,7 +139,7 @@ def extra_repr(self):
         return f"{tuple(self.weight.shape)}, eps={self.eps}"
 
 
-if not (_is_cuda or _is_hip):
+if not _is_cuda:
     logger.info(
         "sgl-kernel is not available on Non-NV platforms. Fallback to other kernel libraries."
     )