Staging: vt6655: Checkpatch fix: c99 comment headings

This patch fixes some of the following checkpatch.pl errors in mac.h
ERROR: do not use C99 // comments

This patch reformats all single line c99 style comments to the
preferred style.
Signed-off-by: Emrys Bayliss <emrys@paradise.net.nz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>