staging: vt6656: removed custom 802.11 header usage

Removed struct tagS802_11Header, switching to struct ieee80211_hdr instead.
Checkpatch warnings and errors were not resolved.

Signed-off-by: Andres More <more.andres@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>