Staging: rtl8192u: Fix do not use // c99 comments.

This patch fixes checkpatch.pl issues with "do not use // C99 comments" errors in ieee80211_rx.c

Signed-off-by: Dilek Uzulmez <dilekuzulmez@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>