cxgb4: add EOTID tracking and software context dump

Rework and add support for dumping EOTID software context used by
TC-MQPRIO. Also track number of EOTIDs in use.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>