[LIBERTAS]: set dnld_sent correctly for CF parts

Corrects a minor bug with priv->dnld_sent being set incorrectly in
if_cs_host_to_card.

Signed-off-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>