IB/mlx5: Define interface bits for IPoIB offloads

The HW can supply several offloads for UD QP, added  offloads for
checksumming for both TX and RX and LSO for TX.
Two new bits were added in order to expose and enable these offloads:
1. HCA capability bit: declares the support for IPoIB basic offloads.
2. QPC bit which will be used in the QP creation flow, which set these
abilities in the QP.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Reviewed-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>