[llvm] [RISCV][Disassemble] Ensure the comment stream of the disassembler is set. (PR #125962)

[Craig Topper via llvm-commits]

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@@ -131,6 +131,11 @@ class MCDisassembler {
   ///                   MCDisassembler::SoftFail if the instruction was
   ///                                            disassemblable but invalid,
   ///                   MCDisassembler::Fail if the instruction was invalid.
+  ///
+  /// Note: to avoid potential issues caused by the field
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topperc wrote:

The majority of the targets don't do this.

https://github.com/llvm/llvm-project/pull/125962