netlink: specs: rt-route: describe lwt BPF program options

Replace binary BPF attributes with a nested lwt-bpf-prog to support
lwt bpf prog options.

Signed-off-by: Hangbin Liu <liuhangbin@kylinos.cn>
Link: https://patch.msgid.link/20261008-ynl_rt_encap-v4-5-4ed2ccf7f949@kylinos.cn
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/rt-route.yaml

@@ -469,13 +469,16 @@ attribute-sets:
     attributes:
       -
         name: in
-        type: binary  # bpf prog
+        type: nest
+        nested-attributes: lwt-bpf-prog
       -
         name: out
-        type: binary
+        type: nest
+        nested-attributes: lwt-bpf-prog
       -
         name: xmit
-        type: binary
+        type: nest
+        nested-attributes: lwt-bpf-prog
       -
         name: xmit-headroom
         type: u32
@@ -603,6 +606,18 @@ attribute-sets:
       -
         name: hwid
         type: u8
+  -
+    name: lwt-bpf-prog
+    name-prefix: lwt-bpf-prog-
+    attributes:
+      -
+        name: fd
+        type: u32
+      -
+        name: name
+        type: string
+        checks:
+          max-len: 256
 
 operations:
   enum-model: directional