[mlir-tblgen] Remove unused "using" decls (NFC) (llvm#139400)

Author: kazutakahirata

mlir/tools/mlir-tblgen/DirectiveCommonGen.cpp

@@ -23,7 +23,6 @@
 using llvm::Clause;
 using llvm::ClauseVal;
 using llvm::raw_ostream;
-using llvm::Record;
 using llvm::RecordKeeper;
 
 // LLVM has multiple places (Clang, Flang, MLIR) where information about

mlir/tools/mlir-tblgen/TosaUtilsGen.cpp

@@ -32,22 +32,12 @@
 #include <list>
 #include <optional>
 
-using llvm::ArrayRef;
 using llvm::formatv;
 using llvm::raw_ostream;
-using llvm::raw_string_ostream;
 using llvm::Record;
 using llvm::RecordKeeper;
-using llvm::SmallVector;
-using llvm::SMLoc;
 using llvm::StringMap;
 using llvm::StringRef;
-using mlir::tblgen::Attribute;
-using mlir::tblgen::EnumCase;
-using mlir::tblgen::EnumInfo;
-using mlir::tblgen::NamedAttribute;
-using mlir::tblgen::NamedTypeConstraint;
-using mlir::tblgen::NamespaceEmitter;
 using mlir::tblgen::Operator;
 
 //===----------------------------------------------------------------------===//