[network] Wiznet Ethernet performance improvements

[scott-brust]

Problem

Ethernet performance on P2 platforms is slower and less reliable compared to gen3 implementations

Solution

This PR improves ethernet performance with a number of changes

• [p2][photon2] Improve ethernet speed by disabling debounce detection on wiznet interrupt pin
• [all] Filter IPV6 packets, as they are not currently fully supported
• [all] Limit the number of frames the wiznet driver can input into the lwip stack based on number of packet buffers available
• [all] Avoid dropping packets if the size header can be read but there is no buffer available for the packet data itself.

Steps to Test

Enable ethernet on a P2/Photon2 platform

Example App

See tinker

References

Credit to @avtolstoy as original author