ethdev: change promiscuous callbacks to return status

ethdev: change promiscuous callbacks to return status

Enabling/disabling of promiscuous mode is not always successful and
it should be taken into account to be able to handle it properly.

When correct return status is unclear from driver code, -EAGAIN is used.

Signed-off-by: Andrew Rybchenko <arybchenko@solarflare.com>
Acked-by: Matan Azrad <matan@mellanox.com>
Acked-by: Hyong Youb Kim <hyonkim@cisco.com>