netlink: specs: rt-link: Add attributes for hsr

YNL wasn't able to decode the linkinfo from hsr interfaces. Add the
linkinfo attribute definitions for hsr interfaces. Example output now
looks like this:

$ ynl --spec Documentation/netlink/specs/rt-link.yaml --do getlink \
    --json '{"ifname": "hsr0"}' --output-json | jq .linkinfo
{
  "kind": "hsr",
  "data": {
    "slave1": 15,
    "slave2": 13,
    "supervision-addr": "01:15:4e:00:01:00",
    "seq-nr": 64511,
    "version": 1,
    "protocol": 0
  }
}

Signed-off-by: Felix Maurer <fmaurer@redhat.com>
Link: https://patch.msgid.link/926077a70de614f1539c905d06515e258905255e.1762968225.git.fmaurer@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/rt-link.yaml

@@ -1913,6 +1913,35 @@ attribute-sets:
         name: port-range
         type: binary
         struct: ifla-geneve-port-range
+  -
+    name: linkinfo-hsr-attrs
+    name-prefix: ifla-hsr-
+    attributes:
+      -
+        name: slave1
+        type: u32
+      -
+        name: slave2
+        type: u32
+      -
+        name: multicast-spec
+        type: u8
+      -
+        name: supervision-addr
+        type: binary
+        display-hint: mac
+      -
+        name: seq-nr
+        type: u16
+      -
+        name: version
+        type: u8
+      -
+        name: protocol
+        type: u8
+      -
+        name: interlink
+        type: u32
   -
     name: linkinfo-iptun-attrs
     name-prefix: ifla-iptun-
@@ -2299,6 +2328,9 @@ sub-messages:
       -
         value: geneve
         attribute-set: linkinfo-geneve-attrs
+      -
+        value: hsr
+        attribute-set: linkinfo-hsr-attrs
       -
         value: ipip
         attribute-set: linkinfo-iptun-attrs