[LLVM][NFC] Remove redundant copy parameter in lambda

Author: AmrDeveloper

llvm/lib/AsmParser/LLParser.cpp

@@ -5239,7 +5239,7 @@ bool LLParser::parseDISubrange(MDNode *&Result, bool IsDistinct) {
   Metadata *UpperBound = nullptr;
   Metadata *Stride = nullptr;
 
-  auto convToMetadata = [&](MDSignedOrMDField Bound) -> Metadata * {
+  auto convToMetadata = [&](const MDSignedOrMDField& Bound) -> Metadata * {
     if (Bound.isMDSignedField())
       return ConstantAsMetadata::get(ConstantInt::getSigned(
           Type::getInt64Ty(Context), Bound.getMDSignedValue()));
@@ -5271,7 +5271,7 @@ bool LLParser::parseDIGenericSubrange(MDNode *&Result, bool IsDistinct) {
   PARSE_MD_FIELDS();
 #undef VISIT_MD_FIELDS
 
-  auto ConvToMetadata = [&](MDSignedOrMDField Bound) -> Metadata * {
+  auto ConvToMetadata = [&](const MDSignedOrMDField& Bound) -> Metadata * {
     if (Bound.isMDSignedField())
       return DIExpression::get(
           Context, {dwarf::DW_OP_consts,