net: if: Init must be called before setting the name

As the interface init function might configure the system
such a way that would affect the naming of the network
interface, we need to call the init before setting the name.
This is mostly needed by Wifi where the Wifi driver needs
to mark its network interface as Wifi interface as by default
the Wifi interface will look like Ethernet one.

Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>