panfrost: Merge PAN_BO_IMPORTED/PAN_BO_EXPORTED

Always checked together and really signal the same property from
different perspectives.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5859>
3 files changed