cnic: Finetune iSCSI connection reset.

For bnx2 devices, always send notification to bnx2i to let it initiate
the cleanup when RST is received.

For bnx2x devices, add unsolicited RST_COMP handling to start the cleanup.

Signed-off-by: Eddie Wai <waie@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>