[mlir][NFC] Use explicit ::mlir namespace in mlir-tblgen generated code

mlir/tools/mlir-tblgen/OpDefinitionsGen.cpp

auto emit = [&](AttrParamKind attrType, TypeParamKind paramKind,
 
     if (inferType) {
       // Generate builder that infers type too.
       // TODO: Subsume this with general checking if type can be
       // inferred automatically.
       // TODO: Expand to handle regions.
       body << formatv(R"(
         ::llvm::SmallVector<::mlir::Type, 2> inferredReturnTypes;
-        if (succeeded({0}::inferReturnTypes(odsBuilder.getContext(),
+        if (::mlir::succeeded({0}::inferReturnTypes(odsBuilder.getContext(),
                       {1}.location, {1}.operands,
                       {1}.attributes.getDictionary({1}.getContext()),
                       /*regions=*/{{}, inferredReturnTypes)))
           {1}.addTypes(inferredReturnTypes);
         else
           ::llvm::report_fatal_error("Failed to infer result type(s).");)",
                       opClass.getClassName(), builderOpState);
       return;
body << llvm::formatv(
         "  for (unsigned i = 0; i != {0}; ++i)\n",
         (op.getNumVariadicRegions() ? "numRegions" : Twine(numRegions)));
     body << "    (void)" << builderOpState << ".addRegion();\n";
   }
 
   // Result types
   body << formatv(R"(
     ::mlir::SmallVector<::mlir::Type, 2> inferredReturnTypes;
-    if (succeeded({0}::inferReturnTypes(odsBuilder.getContext(),
+    if (::mlir::succeeded({0}::inferReturnTypes(odsBuilder.getContext(),
                   {1}.location, operands,
                   {1}.attributes.getDictionary({1}.getContext()),
                   /*regions=*/{{}, inferredReturnTypes))) {{)",
                   opClass.getClassName(), builderOpState);
   if (numVariadicResults == 0 || numNonVariadicResults != 0)
     body << "  assert(inferredReturnTypes.size()"
          << (numVariadicResults != 0 ? " >= " : " == ") << numNonVariadicResults
          << "u && \"mismatched number of return types\");\n";
void OpEmitter::genPrinter() {
   fctx.addSubst("cppClass", opClass.getClassName());
   auto printer = stringInit->getValue().ltrim().rtrim(" \t\v\f\r");
   method->body() << "  " << tgfmt(printer, &fctx);
 }
 
 void OpEmitter::genVerifier() {
   auto *method = opClass.addMethodAndPrune("::mlir::LogicalResult", "verify");
   auto &body = method->body();
-  body << "  if (failed(" << op.getAdaptorName()
+  body << "  if (::mlir::failed(" << op.getAdaptorName()
        << "(*this).verify((*this)->getLoc()))) "
        << "return ::mlir::failure();\n";
 
   auto *valueInit = def.getValueInit("verifier");
   StringInit *stringInit = dyn_cast<StringInit>(valueInit);
   bool hasCustomVerify = stringInit && !stringInit->getValue().empty();
   populateSubstitutions(op, "(*this)->getAttr", "this->getODSOperands",
                         "this->getODSResults", verifyCtx);