RDMA/nldev: Reshuffle the code to avoid need to rebind QP in error path

RDMA/nldev: Reshuffle the code to avoid need to rebind QP in error path

Properly unwind QP counter rebinding in case of failure.

Trying to rebind the counter after unbiding it is not going to work
reliably, move the unbind to the end so it doesn't have to be unwound.

Fixes: 141a164d7363 ("RDMA/nldev: Allow counter manual mode configration through RDMA netlink")
Link: https://lore.kernel.org/r/20191002115627.16740-1-leon@kernel.org
Reviewed-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>