staging: vt6656: Move tx_key inside vnt_fill_txkey.

tx_key can be got directly from info.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Link: https://lore.kernel.org/r/1b964a6c-5cf7-e675-cf53-3a632acc0be9@gmail.com


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