staging: vt6656: rxtx.c create structure to join vnt_tx_data_head with vnt_tx_head.

Create struct vnt_tx_mic_hdr for with union vnt_tx_data_head
for mic mode.

Create union vnt_tx for mic and non mic mode.

Attach vnt_rrv_time_* to relevant tx_head.

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