netdev-genl: Hold rcu_read_lock in napi_set

Hold rcu_read_lock during netdev_nl_napi_set_doit, which calls
napi_by_id and requires rcu_read_lock to be held.

Closes: https://lore.kernel.org/netdev/719083c2-e277-447b-b6ea-ca3acb293a03@redhat.com/


Fixes: 1287c1ae ("netdev-genl: Support setting per-NAPI config values")
Signed-off-by: Joe Damato <jdamato@fastly.com>
Link: https://patch.msgid.link/20241114175600.18882-1-jdamato@fastly.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>