Writers in perhaps any language, and certainly this is true of English, will sometimes co-opt an unusual word and use it in place of a more common word just to catch the reader's attention with a new way of saying something, as opposed to saying it in the common, trite way.
However, in this case, I would not choose "stifle" to take the place of "choke" for the simple reason that it would be underwhelming. It would be akin to saying "hit" instead of "smash." Usually writers prefer to emphasize something, rather than to understate it.
In normal usage, "stifle" implies hindering or impeding. The dictionary may say "restrain." It can mean "suffocating," but it would never reach the level of fatality--it just means that breathing becomes very difficult.
It also depends on the manner of "suffocation." If one is suffocated through the use of physical force, such as hands around the neck or a hangman's noose, the word "stifle" would seem out of place. Nor would "stifle" apply if one has drowned underwater. If, however, one has a thick cloth or pillow placed over the face, then "stifle" might apply. Again, the connotation with "stifle" is that breathing is made very difficult--not necessarily impossible.