IB/rxe: Remove a pointless indirection layer

Neither rxe->ifc_ops nor any of the function pointers in struct
struct rxe_ifc_ops ever change. Hence remove the rxe->ifc_ops
indirection mechanism.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Andrew Boyer <andrew.boyer@dell.com>
Cc: Moni Shoua <monis@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>