Merge branch 'net-convert-af_netlink-and-af_vsock-to-getsockopt_iter-api'

Breno Leitao says:

====================
net: Convert AF_NETLINK and AF_VSOCK to getsockopt_iter API

Continue the work to convert protocols to the new getsockopt_iter API.

Convert AF_NETLINK and AF_VSOCK getsockopt implementations to the new
sockopt_t/getsockopt_iter API, and add kselftests that verify the size
and errno semantics are preserved across the conversion.

I chose these two socket families because they are probably one of the
most used  protocols,, ensuring that any potential bugs will be
discovered and reported quickly.
====================

Link: https://patch.msgid.link/20260501-getsock_one-v1-0-810ce23ea70e@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>