cxgb4: handle interrupt raised when FW crashes

Handle TIMER0INT when FW crashes. Check for PCIE_FW[FW_EVAL]
and if it says "Device FW Crashed", then treat it as fatal.
Else, non-fatal.

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