drm/vmwgfx: Fix hibernation device reset

The device would not reset properly when resuming from hibernation.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Dmitry Torokhov <dtor@vmware.com>
Cc: stable@vger.kernel.org
Cc: linux-graphics-maintainer@vmware.com
Signed-off-by: Dave Airlie <airlied@redhat.com>