MFC r273480, r273750, r273753, r273797, and r274461.

r273480:
cxgbe/iw_cxgbe: wake up waiters after flushing the qp.

r273750:
Some cxgbe/iw_cxgbe fixes:

• Free rt in c4iw_connect only if it is allocated.
• Call soclose instead of so_shutdown if there is an abort from the peer.
• Close socket and return failure if TOE is not enabled.

r273753:
iwcm_event status needs to be populated for close_complete_upcall

r273797:
Always request a completion for every work request for iWARP. The
initial MPA exchange must be tracked this way so that t4_tom's state for
the tid is all clean at the time the tid transitions to RDMA mode. Once
it does, t4_tom is out of the way and iw_cxgbe uses the qp endpoints
directly.

r274461:
iw_cxgbe: don't forget to close the socket in c4iw_connect if soconnect
fails.