staging: vt6656: move key frag controls to vnt_fill_txkey

vnt_fill_txkey now has access to tx_buffer move cipher frag controls

The icv_len is the only thing needed from hw_key in vnt_tx_packet.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/bb91b159-387a-005b-f614-c541de128c40@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>