octeontx2-pf: mcs: Fix NULL pointer dereferences

octeontx2-pf: mcs: Fix NULL pointer dereferences

When system is rebooted after creating macsec interface
below NULL pointer dereference crashes occurred. This
patch fixes those crashes by using correct order of teardown

[ 3324.406942] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[ 3324.415726] Mem abort info:
[ 3324.418510]   ESR = 0x96000006
[ 3324.421557]   EC = 0x25: DABT (current EL), IL = 32 bits
[ 3324.426865]   SET = 0, FnV = 0
[ 3324.429913]   EA = 0, S1PTW = 0
[ 3324.433047] Data abort info:
[ 3324.435921]   ISV = 0, ISS = 0x00000006
[ 3324.439748]   CM = 0, WnR = 0
....
[ 3324.575915] Call trace:
[ 3324.578353]  cn10k_mdo_del_secy+0x24/0x180
[ 3324.582440]  macsec_common_dellink+0xec/0x120
[ 3324.586788]  macsec_notify+0x17c/0x1c0
[ 3324.590529]  raw_notifier_call_chain+0x50/0x70
[ 3324.594965]  call_netdevice_notifiers_info+0x34/0x7c
[ 3324.599921]  rollback_registered_many+0x354/0x5bc
[ 3324.604616]  unregister_netdevice_queue+0x88/0x10c
[ 3324.609399]  unregister_netdev+0x20/0x30
[ 3324.613313]  otx2_remove+0x8c/0x310
[ 3324.616794]  pci_device_shutdown+0x30/0x70
[ 3324.620882]  device_shutdown+0x11c/0x204

[  966.664930] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  966.673712] Mem abort info:
[  966.676497]   ESR = 0x96000006
[  966.679543]   EC = 0x25: DABT (current EL), IL = 32 bits
[  966.684848]   SET = 0, FnV = 0
[  966.687895]   EA = 0, S1PTW = 0
[  966.691028] Data abort info:
[  966.693900]   ISV = 0, ISS = 0x00000006
[  966.697729]   CM = 0, WnR = 0
[  966.833467] Call trace:
[  966.835904]  cn10k_mdo_stop+0x20/0xa0
[  966.839557]  macsec_dev_stop+0xe8/0x11c
[  966.843384]  __dev_close_many+0xbc/0x140
[  966.847298]  dev_close_many+0x84/0x120
[  966.851039]  rollback_registered_many+0x114/0x5bc
[  966.855735]  unregister_netdevice_many.part.0+0x14/0xa0
[  966.860952]  unregister_netdevice_many+0x18/0x24
[  966.865560]  macsec_notify+0x1ac/0x1c0
[  966.869303]  raw_notifier_call_chain+0x50/0x70
[  966.873738]  call_netdevice_notifiers_info+0x34/0x7c
[  966.878694]  rollback_registered_many+0x354/0x5bc
[  966.883390]  unregister_netdevice_queue+0x88/0x10c
[  966.888173]  unregister_netdev+0x20/0x30
[  966.892090]  otx2_remove+0x8c/0x310
[  966.895571]  pci_device_shutdown+0x30/0x70
[  966.899660]  device_shutdown+0x11c/0x204
[  966.903574]  __do_sys_reboot+0x208/0x290
[  966.907487]  __arm64_sys_reboot+0x20/0x30
[  966.911489]  el0_svc_handler+0x80/0x1c0
[  966.915316]  el0_svc+0x8/0x180
[  966.918362] Code: f9400000 f9400a64 91220014 f94b3403 (f9400060)
[  966.924448] ---[ end trace 341778e799c3d8d7 ]---

Fixes: c54ffc73601c ("octeontx2-pf: mcs: Introduce MACSEC hardware offloading")
Signed-off-by: Subbaraya Sundeep <sbhatta@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: Geetha sowjanya <gakula@marvell.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>