drm/amdgpu: move amdgpu_virt_release_full_gpu to fini_early stage

adev->rmmio is set to be NULL in amdgpu_device_unmap_mmio to prevent
access after pci_remove, however, in SRIOV case, amdgpu_virt_release_full_gpu
will still use adev->rmmio for access after amdgpu_device_unmap_mmio.
The patch is to move such SRIOV calling earlier to fini_early stage.

Fixes: 07775fc1

 ("drm/amdgpu: Unmap all MMIO mappings")
Cc: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Leslie Shi <Yuliang.Shi@amd.com>
Signed-off-by: Guchun Chen <guchun.chen@amd.com>
Reviewed-by: Andrey Grodzovsky <andrey.grodzovsky@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>