RDMA/qedr: Rename the qedr_cm file as a preparation for iWARP support

The main differences between iWARP and RoCE lay in the communication
 management functions. These will be placed in separate files.

Signed-off-by: Michal Kalderon <Michal.Kalderon@cavium.com>
Signed-off-by: Ram Amrani <Ram.Amrani@cavium.com>
Signed-off-by: Ariel Elior <Ariel.Elior@cavium.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>