radv: Include flushes in the barrier.

Since the flushes really happen on the next draw delay the barrier
end to include the flushes.

This fixes the barrier duration in RGP.

Reviewed-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6550>
4 files changed