freedreno: Don't return a flushed batch
Somehow fairly recently the traces CI job started hitting timeouts, not
all the time but enough to be inconvenient for CI. I tracked it down to
getting into a situation where `ctx->batch->flush == true`, which causes
an infinite loop in the draw_vbo and clear paths (because
fd_batch_lock_submit() checks for flushed batch but fd_context_batch()
does not). I'm not entirely sure how we get into that state, or what
triggered this (seems possibly triggered by !10937). But it is easy
enough to recover.
Signed-off-by: Rob Clark <robdclark@chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11196>