net: yaip: The core initialize ARP layer relevantly

Up to the core to initialize what's required to get all things working.
Introducing a NET_ARP configuration option, in future this one will be
set if only some hardware requires it along IPv4.

In order to differentiate ARP and actualy hardware drivers supporting
ethernet frames, adding a NET_ETHERNET config option. Which option, if
enabled along NET_SLIP, will be used later on to fully simulate ethernet
over slip TAP driver. Such option will also be used to unlock ethernet
hardware devices in drivers in future.

Change-Id: I10ed151b96256ea3f265c3926bf9a35e49692e1e
Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>