staging: rtl8712: add period within a comment

Add a period to separate repeated words in a comment. The period preserves
the meaning of the comment while also stopping the checkpatch warning:
WARNING: Possible repeated word: 'fw'.

Signed-off-by: Deborah Brouwer <deborahbrouwer3563@gmail.com>
Link: https://lore.kernel.org/r/f9f48ac6e93e814c51a7ed370d0b2988d2e3a602.1617674639.git.deborahbrouwer3563@gmail.com


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