pm80xx: Updated link rate

Updated 12G linkrate to libsas.

Signed-off-by: Viswas G <Viswas.G@pmcs.com>
Reviewed-by: Suresh Thiagarajan <Suresh.Thiagarajan@pmcs.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Jack Wang <jinpu.wang@profitbricks.com>
Reviewed-by: Tomas Henzl <thenzl@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Odin.com>