carl9170: fix copy and paste mishap in carl9170_handle_mpdu

This patch fixes a regression which was introduced by:
"carl9170: split up carl9170_handle_mpdu"

Previously, the ieee80211_rx_status was kept on the
stack of carl9170_handle_mpdu. Now it's passed into
the function as a pointer parameter. Hence, the old
memcpy call needs to be fixed.

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>