Revert "ath9k: Fix general protection fault in ath9k_hif_usb_rx_cb"

This reverts commit b5c8896b which is
commit 2bbcaaee

 upstream.

It is being reverted upstream, just hasn't made it there yet and is
causing lots of problems.

Reported-by: Hans de Goede <hdegoede@redhat.com>
Cc: Qiujun Huang <hqjagain@gmail.com>
Cc: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>