bnxt_en: Fix xmit_more with BQL.

bnxt_en: Fix xmit_more with BQL.

Orabug: 26402533, 26325599, 26366387

We need to write the doorbell if BQL has stopped the queue and
skb->xmit_more is set.  Otherwise it is possible for the tx queue to
rot and cause tx timeout.

Fixes: 4d172f21cefe ("bnxt_en: Implement xmit_more.")
Suggested-by: Yuval Mintz <yuval.mintz@cavium.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit ffe406457753a7ca2061ecc8c4d3971623066911)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Somasundaram Krishnasamy <somasundaram.krishnasamy@oracle.com>