[CIR][MLIR][OpenMP] Enable the MarkDeclareTarget pass for ClangIR (#189420)
This patch enables the MarkDeclareTarget for CIR by adding the pass to
the lowerings and attaching the declare target interface to the
cir::FuncOp. The MarkDeclareTarget is also generalized to work on the
FunctionOpInterface instead of func::Op since it needs to be able to
handle cir::FuncOp as well.
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>