af_packet: remove UNIX_FILE_EVENT_EDGE_TRIGGERED flag

af_packet: remove UNIX_FILE_EVENT_EDGE_TRIGGERED flag

af_packet does not process data until the interface is UP. If after interface creation, but before it is UP, the host interfaces are flooded, then blocking case may occur - VPP interface will never be able to process the data.
If the EDGE_TRIGGERED flag is set, the event will not arrive, because nothing new is happening anymore (probably because the queue is already full).
Therefore, we need to use LEVEL_TRIGGERED (default value), which indicates that there is still unprocessed data (accumulated after interface creation, but before it was UP).

Type: fix

Signed-off-by: Artem Glazychev <artem.glazychev@xored.com>
Change-Id: Ied459fd194149d09f226bcb0a5907b3e327b148a