Sync with smoltcp updates
- smoltcp removed the
ArpCachetrait in favor of
NB: This breaks the use of loopback and sending packets to yourself. Do not merge this unless you're okay with these being broken until multiple devices are supported by smoltcp.
I hit compile time errors due to running
make update && make all.
If that is not within the normal workflow, we may want to hold off on this.