Merge backports with 20150424.

Remove part of patch 728e9048c74
"Break the huge lock region of htt tx_lock in tx completion"
because the circular array to track free msdu_ids conflicts with
an upstream change which uses the idr api instead. Changed the lock name
back to tx_lock.

Remove patch 32771de31b1b "Log beacon info."
because it also conflicts and is no longer needed.

Change-Id: If57a66bd7a68947050c05b48272b57617d86f053