Add checks for SO_NO_OFFLOAD in a couple of places that I missed earlier
in r245915.
Add a couple of missing error codes.  Treat CPL_ERR_KEEPALV_NEG_ADVICE as
negative advice and not a fatal error.

MFC after:	3 days
Force the 404-BT card (4 x 1G) to use the "uwire" configuration file.

MFC after:	3 days
Install an extra hold on the newly allocated synq entry so that it
cannot be freed while do_pass_accept_req is running.  This closes a race
where do_pass_establish on another CPU (the driver chose a different
queue for the new tid) expands the synq entry into a full PCB and then
releases the only hold on it, all while do_pass_accept_req is still
running.

MFC after:	3 days