Merge branch 'netlink-add-display-hint-to-ynl'

Donald Hunter says:

====================
netlink: add display-hint to ynl

Add a display-hint property to the netlink schema, to be used by generic
netlink clients as hints about how to display attribute values.

A display-hint on an attribute definition is intended for letting a
client such as ynl know that, for example, a u32 should be rendered as
an ipv4 address. The display-hint enumeration includes a small number of
networking domain-specific value types.
====================

Link: https://lore.kernel.org/r/20230623201928.14275-1-donald.hunter@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>