net: ipconfig: Fix more use after free

While commit 9c706a49

 ("net: ipconfig: fix use after free") avoids
the use after free, the resulting code still ends up calling both the
ic_setup_if() and ic_setup_routes() after calling ic_close_devs(), and
access to the device is still required.

Move the call to ic_close_devs() to the very end of the function.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>