panfrost: Use tiler fast path (performance boost)

panfrost: Use tiler fast path (performance boost)

For reasons that are still unclear (speculation included in the comment
added in this patch), the tiler? metadata has a fast path that we were
not enabling; there looks to be a possible time/memory tradeoff, but the
details remain unclear.

Regardless, this patch improves performance dramatically. Particular
wins are for geometry-heavy scenes. For instance, glmark2-es2's
Phong-shaded bunny, rendering at fullscreen (2400x1600) via GBM, jumped
from ~20fps to hitting vsync cap at 60fps. Gains are even more obvious
when vsync is disabled, as in glmark2-es2-wayland.

With this patch, on GLES 2.0 samples not involving FBOs, it appears
performance is converging with (and sometimes surpassing) the blob.

Signed-off-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>