[mlir][scf] DCE unimplemented decls in TDs (#121237)

More dead code in headers...

Author: makslevental

mlir/include/mlir/Dialect/SCF/IR/SCF.h

@@ -40,12 +40,6 @@ void buildTerminatedBody(OpBuilder &builder, Location loc);
 namespace mlir {
 namespace scf {
 
-// Insert `loop.yield` at the end of the only region's only block if it
-// does not have a terminator already.  If a new `loop.yield` is inserted,
-// the location is specified by `loc`. If the region is empty, insert a new
-// block first.
-void ensureLoopTerminator(Region &region, Builder &builder, Location loc);
-
 /// Returns the loop parent of an induction variable. If the provided value is
 /// not an induction variable, then return nullptr.
 ForOp getForInductionVarOwner(Value val);