drm/amd/display: don't free stolen console memory during suspend

Don't free the memory if we are hitting this as part of suspend.
This way we don't free any memory during suspend; see
amdgpu_bo_free_kernel().  The memory will be freed in the first
non-suspend modeset or when the driver is torn down.

Link: drm/amd#2568


Acked-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>