[mlir] Update cast/isa method calls to function calls

This updates the rest (at implementation) of MLIR's use of cast/isa
method calls where function calls are possible and automatic refactoring
is not. These changes occured in .td files or in macros.

Context:
- https://mlir.llvm.org/deprecation/ at "Use the free function variants for dyn_cast/cast/isa/…"
- Original discussion at https://discourse.llvm.org/t/preferred-casting-style-going-forward/68443