i965: Track when a bo is shared with an external client
If the buffer is being shared with an external client, our own state tracking may be stale and in some cases we may wish to double check with the kernel/hw state. At the moment, this is synonymous with not being reusable, but the semantics between reusable and external are quite different and we will have more examples of non-reusable buffers in the near future. Signed-off-by:Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by:
Kenneth Graunke <kenneth@whitecape.org> Reviewed-by:
Matt Turner <mattst88@gmail.com>