freedreno/a5xx: use MRT0 to import linear zs

A bit of a hack, but we need to do this until we can do tiled zs in
sysmem (and associated tile/until blits for transfer_map).

Fixes xonotic and glmark2 "refract", when reorder wasn't enabled.
(reorder would paper over the issue by avoiding the extra round-
trip to system memory and back to gmem.

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