Staging: vt6655: Fixed ERROR: do not use C99 // comments in vt6655/80211hdr.h

This patch fixes ERROR: do not use C99 // comments found by checkpatch
in vt6655/80211hdr.h.

Signed-off-by: Tülin İzer <tulinizer@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>