cnic: Reset tcp_flags during cnic_cm_create().

Without resetting it, the bnx2i driver cannot use different options for
different iSCSI connections.

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