IB/SA Agent: Add support for SA agent get ClassPortInfo

New SA query function to return the ClassPortInfo struct from the SA.
If the SM supports FullMemberSendOnly mode for MCG's, it sets a
capability bit in the capability_mask2 field of the response.

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