[Performance][MLA][ROCm] Remove redundant D2D copy in deepseek (#27457)

Signed-off-by: ganyi <ygan@amd.com>

csrc/torch_bindings.cpp

@@ -63,7 +63,6 @@ TORCH_LIBRARY_EXPAND(TORCH_EXTENSION_NAME, ops) {
       "    int blocksparse_head_sliding_step) -> ()");
   ops.impl("paged_attention_v2", torch::kCUDA, &paged_attention_v2);
 
-#ifndef USE_ROCM
   // Merge attn states
   // Implements section 2.2 of https://www.arxiv.org/pdf/2501.01005
   // can be used to combine partial attention results (in the split-KV case)
@@ -76,7 +75,7 @@ TORCH_LIBRARY_EXPAND(TORCH_EXTENSION_NAME, ops) {
       "    Tensor suffix_output,"
       "    Tensor suffix_lse) -> ()");
   ops.impl("merge_attn_states", torch::kCUDA, &merge_attn_states);
-
+#ifndef USE_ROCM
   ops.def(
       "convert_vertical_slash_indexes("
       "   Tensor! block_count, Tensor! block_offset, "