IB: Add new InfiniBand link speeds

Introduce support for the following extended speeds:

FDR-10: a Mellanox proprietary link speed which is 10.3125 Gbps with
        64b/66b encoding rather than 8b/10b encoding.
FDR:    IBA extended speed 14.0625 Gbps.
EDR:    IBA extended speed 25.78125 Gbps.

Signed-off-by: Marcel Apfelbaum <marcela@dev.mellanox.co.il>
Reviewed-by: Hal Rosenstock <hal@mellanox.com>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>