drm/amd/display: Fix a list corruption

Remove the private obj from the internal list before we free aconnector.

[   56.925828] BUG: unable to handle page fault for address: ffff8f84a870a560
[   56.933272] #PF: supervisor read access in kernel mode
[   56.938801] #PF: error_code(0x0000) - not-present page
[   56.944376] PGD 18e605067 P4D 18e605067 PUD 86a614067 PMD 86a4d0067 PTE 800ffff8578f5060
[   56.953260] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC NOPTI
[   56.958815] CPU: 6 PID: 1407 Comm: bash Tainted: G           O      5.9.0-rc2+ #46
[   56.967092] Hardware name: System manufacturer System Product Name/PRIME Z390-A, BIOS 1401 11/26/2019
[   56.977162] RIP: 0010:__list_del_entry_valid+0x31/0xa0
[   56.982768] Code: 00 ad de 55 48 8b 17 4c 8b 47 08 48 89 e5 48 39 c2 74 27 48 b8 22 01 00 00 00 00 ad de 49 39 c0 74 2d 49 8b 30 48 39 fe 75 3d <48> 8b 52 08 48 39 f2 75 4c b8 01 00 00 00 5d c3 48 89 7
[   57.003327] RSP: 0018:ffffb40c81687c90 EFLAGS: 00010246
[   57.009048] RAX: dead000000000122 RBX: ffff8f84ea41f4f0 RCX: 0000000000000006
[   57.016871] RDX: ffff8f84a870a558 RSI: ffff8f84ea41f4f0 RDI: ffff8f84ea41f4f0
[   57.024672] RBP: ffffb40c81687c90 R08: ffff8f84ea400998 R09: 0000000000000001
[   57.032490] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000006
[   57.040287] R13: ffff8f84ea422a90 R14: ffff8f84b4129a20 R15: fffffffffffffff2
[   57.048105] FS:  00007f550d885740(0000) GS:ffff8f8509600000(0000) knlGS:0000000000000000
[   57.056979] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   57.063260] CR2: ffff8f84a870a560 CR3: 00000007e5144001 CR4: 00000000003706e0
[   57.071053] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   57.078849] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   57.086684] Call Trace:
[   57.089381]  drm_atomic_private_obj_fini+0x29/0x82 [drm]
[   57.095247]  amdgpu_dm_fini+0x83/0x170 [amdgpu]
[   57.100264]  dm_hw_fini+0x23/0x30 [amdgpu]
[   57.104814]  amdgpu_device_fini+0x1df/0x4fe [amdgpu]
[   57.110271]  amdgpu_driver_unload_kms+0x43/0x70 [amdgpu]
[   57.116136]  amdgpu_pci_remove+0x3b/0x60 [amdgpu]
[   57.121291]  pci_device_remove+0x3e/0xb0
[   57.125583]  device_release_driver_internal+0xff/0x1d0
[   57.131223]  device_release_driver+0x12/0x20
[   57.135903]  pci_stop_bus_device+0x70/0xa0
[   57.140401]  pci_stop_and_remove_bus_device_locked+0x1b/0x30
[   57.146571]  remove_store+0x7b/0x90
[   57.150429]  dev_attr_store+0x17/0x30
[   57.154441]  sysfs_kf_write+0x4b/0x60
[   57.158479]  kernfs_fop_write+0xe8/0x1d0
[   57.162788]  vfs_write+0xf5/0x230
[   57.166426]  ksys_write+0x70/0xf0
[   57.170087]  __x64_sys_write+0x1a/0x20
[   57.174219]  do_syscall_64+0x38/0x90
[   57.178145]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: xinhui pan <xinhui.pan@amd.com>
Acked-by: Feifei Xu <Feifei Xu@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -4993,6 +4993,7 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
 	struct amdgpu_device *adev = drm_to_adev(connector->dev);
 	struct amdgpu_display_manager *dm = &adev->dm;
 
+	drm_atomic_private_obj_fini(&aconnector->mst_mgr.base);
 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) ||\
 	defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)