devlink: don't enforce NETLINK_{CAP,EXT}_ACK sock opts

devlink: don't enforce NETLINK_{CAP,EXT}_ACK sock opts

Since commit 049c58539f5d ("devlink: mnlg: Add support for extended ack")
devlink requires NETLINK_{CAP,EXT}_ACK. This prevents devlink from
working with older kernels that don't support these features.

host # ./devlink/devlink
Failed to connect to devlink Netlink

Fixes: 049c58539f5d ("devlink: mnlg: Add support for extended ack")
Cc: Arkadi Sharshevsky <arkadis@mellanox.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>