mac80211: fix reorder buffer release

My patch "mac80211: correctly place aMPDU RX reorder code"
uses an skb queue for MPDUs that were released from the
buffer. I intentially didn't initialise and use the skb
queue's spinlock, but in this place forgot that the code
variant that doesn't touch the spinlock is needed.

Thanks to Christian Lamparter for quickly spotting the
bug in the backtrace Reinette reported.

Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Bug-identified-by: Christian Lamparter <chunkeey@googlemail.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>