staging: wfx: remove references to WFxxx in comments

The WF200 is the only representative of the WFxxx series and the
development of any successor is not expected. So, for clarity, replace
occurrences of "WFxxx" with "WF200".

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20210913130203.1903622-25-Jerome.Pouiller@silabs.com


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