bnx2x: Fix compile errors if CONFIG_CNIC is not set

Don't provide FCoE and iSCSI statistics to management firmware if
CONFIG_CNIC is not set.  Some needed structure fields are not defined
without CONFIG_CNIC.

Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>