Update the 18xx FW status private part to include Tx related link
priorities. Introduce new HW ops to determine link priority per chip
family.

For 18xx the changes are:
- Suspended links are at most low priority and Tx for them is stopped
  beyond the suspend threshold.
- Active links now get their thresholds directly from FW
- There's a new "stop" threshold for active links, at which point a link
  stops receiving new packets.

Update the min 18xx FW version required to make sure suspended links
bitmap is advertised by the FW.
Signed-off-by: NArik Nemtsov <arik@wizery.com>
Signed-off-by: NLuciano Coelho <coelho@ti.com>