net: warn during dump if NAPI list is not sorted

net: warn during dump if NAPI list is not sorted

Dump continuation depends on the NAPI list being sorted.
Broken netlink dump continuation may be rare and hard to debug
so add a warning if we notice the potential problem while walking
the list.

Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Reviewed-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20250110004505.3210140-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>