llvmpipe: Optimize tile allocation
lp_scene::tile
ends up being 1.5MB on LP64 because it needs to be large
enough to handle a 16k framebuffer, but most framebuffers are much
smaller than that. Dynamically allocate them so we don't waste memory, and so we don't waste time zeroing too much. Improves LP_NO_RAST=1 es2gears_x11
from ~3600 to ~4000
fps.
Edited by Adam Jackson