iw_cxgb4: fix ECN check on the passive accept

iw_cxgb4: fix ECN check on the passive accept

pass_accept_req() is using the same skb for handling accept request and
sending accept reply to HW. Here req and rpl structures are pointing to
same skb->data which is over written by INIT_TP_WR() and leads to
accessing corrupt req fields in accept_cr() while checking for ECN flags.
Reordered code in accept_cr() to fetch correct req fields.

Fixes: f6847a04e9 ("iw_cxgb4: Choose appropriate hw mtu index and ISS for iWARP connections")
Signed-off-by: Potnuri Bharat Teja <bharat@chelsio.com>
Link: https://lore.kernel.org/r/20191003104353.11590-1-bharat@chelsio.com
Signed-off-by: Doug Ledford <dledford@redhat.com>