Add support for PACKET_RX_RING w/ TPACKET_V2

### Description

In issue https://github.com/google/gvisor/issues/6664#issuecomment-935078809 it was discovered that the latest versions of libpcap have removed all non-mmapped packet capture support as of this commit https://github.com/the-tcpdump-group/libpcap/commit/457027ab43ceef03c578984653c0e59eedf5f46b.

Which means latest versions of tcpdump do not work in gVisor. We will need to add support for PACKET_RX_RING w/ TPACKET_v2 at least to be able to support tcpdump. We can punt on PACKET_TX_RING for now as its not required for tcpdump. TPACKET_v3 is more complicated and probably not required at the moment.

### Is this feature related to a specific bug?

https://github.com/google/gvisor/issues/6664

### Do you have a specific solution in mind?

_No response_