netlink: specs: devlink: add pad to the subsets carrying padded u64s

We are missing the pad attribute in a number of subsets.
Worse, dl-attr-stats which is a separate attr space doesn't
define pad, but reuses the value from the root attr set
(DEVLINK_ATTR_PAD). This would break parsing stats on
an arch without CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS.

Link: https://patch.msgid.link/20260915161341.1053476-9-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Documentation/netlink/specs/devlink.yaml

@@ -1065,6 +1065,8 @@ attribute-sets:
         name: dpipe-table-resource-id
       -
         name: dpipe-table-resource-units
+      -
+        name: pad
 
   -
     name: dl-dpipe-table-matches
@@ -1099,6 +1101,8 @@ attribute-sets:
         name: dpipe-entry-action-values
       -
         name: dpipe-entry-counter
+      -
+        name: pad
 
   -
     name: dl-dpipe-entry-match-values
@@ -1237,6 +1241,8 @@ attribute-sets:
         name: resource-unit
       -
         name: resource-occ
+      -
+        name: pad
 
   -
     name: dl-resource-list
@@ -1289,6 +1295,8 @@ attribute-sets:
         name: region-chunk-data
       -
         name: region-chunk-addr
+      -
+        name: pad
 
   -
     name: dl-fmsg
@@ -1329,6 +1337,8 @@ attribute-sets:
         name: health-reporter-auto-dump
       -
         name: health-reporter-burst-period
+      -
+        name: pad
 
   -
     name: dl-attr-stats
@@ -1343,6 +1353,10 @@ attribute-sets:
       -
         name: stats-rx-dropped
         type: u64
+      -
+        name: pad
+        type: pad
+        value: 61
 
   -
     name: dl-trap-metadata