wireguard: netlink: generate netlink code

wireguard: netlink: generate netlink code

This patch adopts netlink policies and command definitions
generated by ynl-gen, thus completing the conversion to YNL.

Given that the old and new policies are functionally identical
and have just been moved to a new file, it serves to verify
that the policies generated from the spec are identical to the
previous policy code.

The following functions are renamed:
  wg_get_device_dump() -> wg_get_device_dumpit()
  wg_set_device()      -> wg_set_device_doit()

The new files are covered by the existing drivers/net/wireguard/
pattern in MAINTAINERS.

No behavioural changes intended.

Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>