cxgb4: Adds CPL support for Shared Receive Queues

- Add srq table query cpl support for srq
- Add cpl_abort_req_rss6 and cpl_abort_rpl_rss6 structs.
- Add accessors, macros to get the SRQ IDX value.

Signed-off-by: Raju Rangoju <rajur@chelsio.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>