AF_XDP sockets checksum verification

[RuiCunhaM]

While looking at the AF_XDP experimental implementation, I noticed that checksums are not verified on the rx path. This means that, contrary to the "default" implementation, packets with an incorrect checksum will be processed as normal.

Since this implementation is still experimental, I am not entirely sure this would be considered an issue. I am mostly curious to understand if this behavior is known and/or intended.