netlink: specs: devlink: populate multi-attr attrs for region read and line card

Three attributes are emitted repeatedly inside their nest:

 - devlink_nl_region_read_fill() calls
   devlink_nl_cmd_region_read_chunk_fill() once per 256 byte unit
 - devlink_nl_region_snapshots_id_put() emits one
   DEVLINK_ATTR_REGION_SNAPSHOT sub-nest per entry on the region's
   snapshot list
 - devlink_nl_linecard_fill() emits one DEVLINK_ATTR_LINECARD_TYPE per
   linecard->types_count entry

In all three cases we're missing the multi-attr properties, and the
attributes themselves are missing from the attr list used by C code gen.

Link: https://patch.msgid.link/20260915161341.1053476-7-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/devlink.yaml

@@ -1264,6 +1264,7 @@ attribute-sets:
     attributes:
       -
         name: region-snapshot
+        multi-attr: true
 
   -
     name: dl-region-snapshot
@@ -1278,6 +1279,7 @@ attribute-sets:
     attributes:
       -
         name: region-chunk
+        multi-attr: true
 
   -
     name: dl-region-chunk
@@ -1360,6 +1362,7 @@ attribute-sets:
     attributes:
       -
         name: linecard-type
+        multi-attr: true
 
   -
     name: dl-selftest-id
@@ -1971,7 +1974,7 @@ operations:
         post: devlink-nl-post-doit
         request:
           value: 42
-          attributes: &region-id-attrs
+          attributes:
             - bus-name
             - dev-name
             - index
@@ -1979,7 +1982,15 @@ operations:
             - region-name
         reply: &region-get-reply
           value: 42
-          attributes: *region-id-attrs
+          attributes:
+            - bus-name
+            - dev-name
+            - index
+            - port-index
+            - region-name
+            - region-size
+            - region-max-snapshots
+            - region-snapshots
       dump:
         request:
           attributes: *dev-id-attrs
@@ -2045,6 +2056,7 @@ operations:
             - index
             - port-index
             - region-name
+            - region-chunks
 
     -
       name: port-param-get
@@ -2444,14 +2456,22 @@ operations:
         post: devlink-nl-post-doit
         request:
           value: 78
-          attributes: &linecard-id-attrs
+          attributes:
             - bus-name
             - dev-name
             - index
             - linecard-index
         reply: &linecard-get-reply
           value: 80
-          attributes: *linecard-id-attrs
+          attributes:
+            - bus-name
+            - dev-name
+            - index
+            - linecard-index
+            - linecard-state
+            - linecard-type
+            - linecard-supported-types
+            - nested-devlink
       dump:
         request:
           attributes: *dev-id-attrs