staging: wfx: remove useless debug statement

In the early age, it was unexpected to access a VIF that did not exist.
With current code, this happens frequently. Having a trace associated on
this event brings absolutely no informations.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20210913130203.1903622-23-Jerome.Pouiller@silabs.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>