cxgb4: update dump collection logic to use compression

Update firmware dump collection logic to use compression when available.
Let collection logic attempt to do compression, instead of returning out
of memory early.

Signed-off-by: Rahul Lakkireddy <rahul.lakkireddy@chelsio.com>
Signed-off-by: Vishal Kulkarni <vishal@chelsio.com>
Signed-off-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>