RDMA/bnxt_re: Fix lifetimes in bnxt_re_task

A work queue cannot just rely on the ib_device not being freed, it must
hold a kref on the memory so that the BNXT_RE_FLAG_IBDEV_REGISTERED check
works.

Fixes: 1ac5a404 ("RDMA/bnxt_re: Add bnxt_re RoCE driver")
Link: https://lore.kernel.org/r/1584117207-2664-3-git-send-email-selvin.xavier@broadcom.com


Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>