cnic: Allocate kcq resource only on devices that support FCoE.

To save memory and to exit IRQ loop quicker on devices that don't support
FCoE.

Reviewed-by: Eddie Wai <eddie.wai@broadcom.com>
Reviewed-by: Bhanu Prakash Gollapudi <bprakash@broadcom.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>