net: shaper: drop redundant xa_lock() bracketing

net: shaper: drop redundant xa_lock() bracketing

The shaper insertion and update code takes xa_lock() explicitly.
Paolo explained that the locking was purely to avoid re-taking
the lock in loops. But it may be mis-read as if it was expecting
readers to be fenced off by xa_lock. Readers of XArray are purely
under RCU. Remove explicit taking of xa_lock().

All writers to hierarchy->shapers are serialized by the netdev
instance lock (or run after netdev is made inaccessible to readers).

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20260609183224.1108521-2-kuba@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>