[TableGen] Fix indentation of generated code. NFC

This line was missing the indent(4) call. Noticed while looking at the
generated code.

Pull Request: #194765

Author: arichardson

llvm/utils/TableGen/AsmMatcherEmitter.cpp

@@ -2617,7 +2617,8 @@ static void emitValidateOperandClass(const CodeGenTarget &Target,
     OS << indent(4)
        << "const unsigned HwMode = "
           "STI.getHwMode(MCSubtargetInfo::HwMode_RegInfo);\n"
-          "Kind = RegClassByHwModeMatchTable[HwMode][Kind - (MCK_LAST_REGISTER "
+       << indent(4)
+       << "Kind = RegClassByHwModeMatchTable[HwMode][Kind - (MCK_LAST_REGISTER "
           "+ 1)];\n"
           "  }\n\n";
   }