staging: vt6656: merge data positions for packet types a and b into vnt_rxtx_ab

add rts positions from s_vFillRTSHead

add need_mic and remaining union vnt_tx_data_head head positions from
s_vGenerateTxParameter for packet type PK_TYPE_11A and PK_TYPE_11B..

As there are no other possibilities for packet types in  s_vGenerateTxParameter
the if becomes else.

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