[llvm] [TableGen] Fix OperandMap table size (PR #125424)

[Mariusz Sikora via llvm-commits]

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@@ -300,8 +300,8 @@ void InstrInfoEmitter::emitOperandNameMappings(
     assert(MaxOperandNo <= INT16_MAX &&
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mariusz-sikora-at-amd wrote:

`OS << "assert(NamesIdx < OPERAND_LAST);";` ?

https://github.com/llvm/llvm-project/pull/125424