irnodemap: Remove the unused and pointless function ir_nodemap_remove().

ir/ir/irnodemap.h

@@ -73,16 +73,6 @@ static inline void ir_nodemap_insert_fast(ir_nodemap *nodemap,
 	nodemap->data[idx] = data;
 }
 
-/**
- * Removed mapping for @p node.
- *
- * This is really a shorthand form for ir_nodemap_insert(nodemap, node, NULL);
- */
-static inline void ir_nodemap_remove(ir_nodemap *nodemap, const ir_node *node)
-{
-	ir_nodemap_insert(nodemap, node, NULL);
-}
-
 /**
  * Get mapping for @p node. Returns NULL if nothing is mapped.
  */