bnxt: add a missing rcu synchronization

bnxt: add a missing rcu synchronization

Orabug: 24567991

Add a missing synchronize_net() call to avoid potential use after free,
since we explicitly call napi_hash_del() to factorize the RCU grace
period.

Fixes: c0c050c58d84 ("bnxt_en: New Broadcom ethernet driver.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Michael Chan <michael.chan@broadcom.com>
Acked-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit e5f6f564fd191d365fcd775c06a732a488205588)
Signed-off-by: Brian Maly <brian.maly@oracle.com>
Signed-off-by: Dhaval Giani <dhaval.giani@oracle.com>