staging: vt6655: replace typedef struct tagSTxDataHead_ab with struct vnt_tx_datahead_ab

Replacing members
ab, wDuration and wTimeStampOff

with
ab, duration and time_stamp_off

All unsigned short should be __le16

Structure is moved to rxtx.h

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>