mlxsw: core: Fix memory leak on module removal

Free the devlink instance during the teardown sequence in the non-reload
case to avoid the following memory leak.

unreferenced object 0xffff888232895000 (size 2048):
  comm "modprobe", pid 1073, jiffies 4295568857 (age 164.871s)
  hex dump (first 32 bytes):
    00 01 00 00 00 00 ad de 22 01 00 00 00 00 ad de  ........".......
    10 50 89 32 82 88 ff ff 10 50 89 32 82 88 ff ff  .P.2.....P.2....
  backtrace:
    [<00000000c704e9a6>] __kmalloc+0x13a/0x2a0
    [<00000000ee30129d>] devlink_alloc+0xff/0x760
    [<0000000092ab3e5d>] 0xffffffffa042e5b0
    [<000000004f3f8a31>] 0xffffffffa042f6ad
    [<0000000092800b4b>] 0xffffffffa0491df3
    [<00000000c4843903>] local_pci_probe+0xcb/0x170
    [<000000006993ded7>] pci_device_probe+0x2c2/0x4e0
    [<00000000a8e0de75>] really_probe+0x2c5/0xf90
    [<00000000d42ba75d>] driver_probe_device+0x1eb/0x340
    [<00000000bcc95e05>] device_driver_attach+0x294/0x300
    [<000000000e2bc177>] __driver_attach+0x167/0x2f0
    [<000000007d44cd6e>] bus_for_each_dev+0x148/0x1f0
    [<000000003cd5a91e>] driver_attach+0x45/0x60
    [<000000000041ce51>] bus_add_driver+0x3b8/0x720
    [<00000000f5215476>] driver_register+0x230/0x4e0
    [<00000000d79356f5>] __pci_register_driver+0x190/0x200

Fixes: a22712a9 ("mlxsw: core: Fix devlink unregister flow")
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reported-by: Vadim Pasternak <vadimp@nvidia.com>
Tested-by: Oleksandr Shamray <oleksandrs@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/mellanox/mlxsw/core.c

@@ -2064,6 +2064,8 @@ void mlxsw_core_bus_device_unregister(struct mlxsw_core *mlxsw_core,
 	if (!reload)
 		devlink_resources_unregister(devlink, NULL);
 	mlxsw_core->bus->fini(mlxsw_core->bus_priv);
+	if (!reload)
+		devlink_free(devlink);
 
 	return;