Revert "drm/amdgpu: TA unload messages are not actually sent to psp when amdgpu is...

Revert "drm/amdgpu: TA unload messages are not actually sent to psp when amdgpu is uninstalled"

[ Upstream commit b9a3a4fccc9d7945d196c154fd35302fca383c83 ]

This reverts commit c15966c1aa2f22f6ad3ee895210df712f2246d5f.
The following change: move the drm_dev_unplug call after
amdgpu_driver_unload_kms in amdgpu_pci_remove. The reason is
the following: amdgpu_pci_remove calls drm_dev_unregister
and it should be called first to ensure userspace can't access the
device instance anymore. If we call drm_dev_unplug after
amdgpu_driver_unload_kms then we observe IGT PCI software unplug
test failure (kernel hung) for all ASICs. This is how this
regression was found.

After this revert, the following commands do work not, but it would
be fixed in the next commit:
 - sudo modprobe -r amdgpu
 - sudo modprobe amdgpu

Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Reviewed-by Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>