net/mlx5: Register devlink first under devlink lock

In the Linux kernel, the following vulnerability has been resolved:

net/mlx5: Register devlink first under devlink lock

In case device is having a non fatal FW error during probe, the
driver will report the error to user via devlink. This will trigger
a WARN_ON, since mlx5 is calling devlink_register() last.
In order to avoid the WARN_ON[1], change mlx5 to invoke devl_register()
first under devlink lock.

[1]
WARNING: CPU: 5 PID: 227 at net/devlink/health.c:483 devlink_recover_notify.constprop.0+0xb8/0xc0
CPU: 5 PID: 227 Comm: kworker/u16:3 Not tainted 6.4.0-rc5_for_upstream_min_debug_2023_06_12_12_38 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: mlx5_health0000:08:00.0 mlx5_fw_reporter_err_work [mlx5_core]
RIP: 0010:devlink_recover_notify.constprop.0+0xb8/0xc0
Call Trace:
<TASK>
? __warn+0x79/0x120
? devlink_recover_notify.constprop.0+0xb8/0xc0
? report_bug+0x17c/0x190
? handle_bug+0x3c/0x60
? exc_invalid_op+0x14/0x70
? asm_exc_invalid_op+0x16/0x20
? devlink_recover_notify.constprop.0+0xb8/0xc0
devlink_health_report+0x4a/0x1c0
mlx5_fw_reporter_err_work+0xa4/0xd0 [mlx5_core]
process_one_work+0x1bb/0x3c0
? process_one_work+0x3c0/0x3c0
worker_thread+0x4d/0x3c0
? process_one_work+0x3c0/0x3c0
kthread+0xc6/0xf0
? kthread_complete_and_exit+0x20/0x20
ret_from_fork+0x1f/0x30
</TASK>