net: shaper: annotate the data races

net: shaper: annotate the data races

As previously discussed we don't care about making the shaper
state fully RCU-compliant because the hierarchy itself can't
be dumped in one go over Netlink. Let's annotate the reads
and writes to make that clear.

The field-by-field assignments will also be useful for the
next commit which adds explicit "valid" field (which we don't
want to override with the current full struct assignment).

Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260515221325.1685455-2-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>