[mlir] (NFC) Clean up bazel and CMake target names All dialect targets in bazel have been named *Dialect and all dialect targets in CMake have been named MLIR*Dialect.
[mlir] move SCF headers to SCF/{IR,Transforms} respectively This aligns the SCF dialect file layout with the majority of the dialects. Reviewed By: jpienaar Differential Revision: https://reviews.llvm.org/D128049