Despite the fact that all callers to dev_map_lookup are ensuring that
there is always device name prior to call to that function, it is better
and safer to check that in the dev_map_lookup itself.
Fixes: 40df8263a0 ("rdma: Add dev object")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
99da90326e