iw_cxgb4: use tos when importing the endpoint

import_ep() is passed the correct tos, but doesn't use it correctly.

Fixes: ac8e4c69 ("cxgb4/iw_cxgb4: TOS support")
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>