netlink: specs: add display hints to ovs_flow

Add display hints for mac, ipv4, ipv6, hex and uuid to the ovs_flow
schema.

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Link: https://lore.kernel.org/r/20230623201928.14275-4-donald.hunter@gmail.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>