net/bnxt: fix Tx with multiple mbuf

net/bnxt: fix Tx with multiple mbuf

When using multi-mbuf to xmit large packets, we need to use total
packet lengths (sum of all segments) to set txbd->flags_type.
Packets will not be sent when using tx_pkt->data_len(The first
segment of packets).

Fixes: 6eb3cc2294fd ("net/bnxt: add initial Tx code")
Cc: stable@dpdk.org
Signed-off-by: Xiaoxin Peng <xiaoxin.peng@broadcom.com>
Reviewed-by: Herry Chen <herry.chen@broadcom.com>
Reviewed-by: Jason He <jason.he@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>