bnxt_en: bring back rtnl_lock() in the bnxt_open() path

bnxt_en: bring back rtnl_lock() in the bnxt_open() path

Error recovery, PCIe AER, resume, and TX timeout will invoke bnxt_open()
with netdev_lock only.  This will cause RTNL assert failure in
netif_set_real_num_tx_queues(), netif_set_real_num_tx_queues(),
and netif_set_real_num_tx_queues().

Example error recovery assert:

RTNL: assertion failed at net/core/dev.c (3178)
WARNING: CPU: 3 PID: 3392 at net/core/dev.c:3178 netif_set_real_num_tx_queues+0x1fd/0x210

Call Trace:
 <TASK>
 ? __pfx_bnxt_msix+0x10/0x10 [bnxt_en]
 __bnxt_open_nic+0x1ef/0xb20 [bnxt_en]
 bnxt_open+0xda/0x130 [bnxt_en]
 bnxt_fw_reset_task+0x21f/0x780 [bnxt_en]
 process_scheduled_works+0x9d/0x400

For now, bring back rtnl_lock() in all these code paths that can invoke
bnxt_open().  In the bnxt_queue_start() error path, we don't have
rtnl_lock held so we just change it to call netif_close() instead of
bnxt_reset_task() for simplicity.  This error path is unlikely so it
should be fine.

Fixes: 004b5008016a ("eth: bnxt: remove most dependencies on RTNL")
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@broadcom.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Reviewed-by: Andy Gospodarek <andrew.gospodarek@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Link: https://patch.msgid.link/20250514062908.2766677-1-michael.chan@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>