etnaviv: do proper cpu prep/fini when clearing allocated buffer

The debug memset 0 of all allocated buffers did not sync the buffer for CPU
access as required by the UAPI.

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/7367>
1 file changed