drm/amdgpu: don't increment vram lost if we are in hibernation

We reset the GPU as part of our hibernation sequence so we need
to make sure we don't mark vram as lost in that case.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=111879


Acked-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>