net/mlx5: Fix peer devlink set for SF representor devlink port

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

net/mlx5: Fix peer devlink set for SF representor devlink port

The cited patch change register devlink flow, and neglect to reflect
the changes for peer devlink set logic. Peer devlink set is
triggering a call trace if done after devl_register.[1]

Hence, align peer devlink set logic with register devlink flow.

[1]
WARNING: CPU: 4 PID: 3394 at net/devlink/core.c:155 devlink_rel_nested_in_add+0x177/0x180
CPU: 4 PID: 3394 Comm: kworker/u40:1 Not tainted 6.9.0-rc4_for_linust_min_debug_2024_04_16_14_08 #1
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014
Workqueue: mlx5_vhca_event0 mlx5_vhca_state_work_handler [mlx5_core]
RIP: 0010:devlink_rel_nested_in_add+0x177/0x180
Call Trace:

? __warn+0x78/0x120
? devlink_rel_nested_in_add+0x177/0x180
? report_bug+0x16d/0x180
? handle_bug+0x3c/0x60
? exc_invalid_op+0x14/0x70
? asm_exc_invalid_op+0x16/0x20
? devlink_port_init+0x30/0x30
? devlink_port_type_clear+0x50/0x50
? devlink_rel_nested_in_add+0x177/0x180
? devlink_rel_nested_in_add+0xdd/0x180
mlx5_sf_mdev_event+0x74/0xb0 [mlx5_core]
notifier_call_chain+0x35/0xb0
blocking_notifier_call_chain+0x3d/0x60
mlx5_blocking_notifier_call_chain+0x22/0x30 [mlx5_core]
mlx5_sf_dev_probe+0x185/0x3e0 [mlx5_core]
auxiliary_bus_probe+0x38/0x80
? driver_sysfs_add+0x51/0x80
really_probe+0xc5/0x3a0
? driver_probe_device+0x90/0x90
__driver_probe_device+0x…