freedreno: add batch-cache and batch reordering

freedreno: add batch-cache and batch reordering

Note that I originally also had a entry-point that would construct a key
and do lookup from a pipe_surface.  I ended up not needing that (yet?)
but it is easy-enough to re-introduce later if we need it for the blit
path.

For now, not enabled by default, but can be enabled (on a3xx/a4xx) with
FD_MESA_DEBUG=reorder.

Signed-off-by: Rob Clark <robdclark@gmail.com>