IB/SA: Rename ib_sa_path_rec to sa_path_rec

Rename ib_sa_path_rec to a more generic sa_path_rec.
This is part of extending ib_sa to also support OPA
path records in addition to the IB defined path records.

Reviewed-by: Don Hiatt <don.hiatt@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dasaratharaman Chandramouli <dasaratharaman.chandramouli@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>