Retcon

A retcon (a portmanteau of "retroactive continuity") is the alteration of previously established facts in a fictional work. Retcons are done for many reasons, including the accommodation of sequels or further derivative works in a series, wherein newer authors or creators want to revise the in-story history to allow a course of events that would not have been possible in the story's original continuity. Other reasons might be the reintroduction of popular characters, resolution of errors in chronology, the updating of a familiar series for modern audiences, or simplification of an excessively complex continuity structure.

Use in Mainstream Smurfs Media
As far as Smurf history goes in the comic book universe, the Smurfs and their village first appeared in a desolate rock-filled forest called the Cursed Land in the comic book story The Smurfs And The Magic Flute, as they were only originally intended to be supporting characters to Sir Johan and Peewit in their series of comic book stories. When the Smurfs became popular enough to warrant a spinoff series of their own, the location of the Smurf Village was changed to a flourishing animal-filled forest seen in all subsequent interpretations of the Smurfs, including the animated version of The Smurfs And The Magic Flute.

As far as explaining the non-appearances of Baby Smurf, the Smurflings, Grandpa Smurf, Wild Smurf, and Nanny Smurf in the 2011 Smurfs movie, it may be that the movie itself is set in a different media universe and is not a retcon (or better termed, a continuity reboot) of Smurf history in the comic book universe.