RDMA/qedr: Remove CQ spinlock from CM completion handlers

There is only a single event queue that triggers the completion
events for the RDMA CM and it is being processed serially. This means
that inherently there can no parallelism of CQ completion handler
callbacks, hence the lock is redundant.

Signed-off-by: Ram Amrani <Ram.Amrani@cavium.com>
Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>