You got a nice Knight mate, but it is not a Smothered Mate, anyway! It is a Knight Mate. Black King had 3 square to breach out, but King cannot goes on.
Smothered mate is only happen when King had No squares at all!, and it schoked in, like on first example above.
/I got a dozen Smothered Mates here at Site, and more than 200 Knight Mates here, at Site.../
I know this is the official smothered mate:
White only uses his knight; no help at all from other friendly pieces. But my game below was close, I only needed 3 pieces!