nfp: flower: avoid taking mutex in atomic context

nfp: flower: avoid taking mutex in atomic context

A mutex may sleep, which is not permitted in atomic context.
Avoid a case where this may arise by moving the to
nfp_flower_lag_get_info_from_netdev() in nfp_tun_write_neigh() spinlock.

Fixes: abc210952af7 ("nfp: flower: tunnel neigh support bond offload")
Reported-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Yanguo Li <yanguo.li@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230131080313.2076060-1-simon.horman@corigine.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>