[mlir] Fix some of the warnings in MLIR code.
Summary:
* extra ';' in the following files:
mlir/lib/Dialect/Linalg/Transforms/Transforms.cpp
mlir/lib/Dialect/Shape/IR/Shape.cpp
* base class ‘mlir::ConvertVectorToSCFBase<ConvertVectorToSCFPass>’
should be explicitly initialized in the copy constructor [-Wextra] in
mlir/lib/Conversion/VectorToSCF/VectorToSCF.cpp
* warning: ‘bool Expression::operator==(const Expression&) const’
defined but not used [-Wunused-function] in
mlir/tools/mlir-linalg-ods-gen/mlir-linalg-ods-gen.cpp
Differential Revision: https://reviews.llvm.org/D81673