radeonsi: initialize SX_PS_DOWNCONVERT to 0 on Stoney
otherwise the SX or CB blocks can go bananas Reviewed-by:Nicolai Hähnle <nicolai.haehnle@amd.com> Cc: mesa-stable@lists.freedesktop.org (cherry picked from commit 40912dd9) [Emil Velikov: resolve trivial conflicts] Signed-off-by:
Emil Velikov <emil.velikov@collabora.com> Conflicts: src/gallium/drivers/radeonsi/si_state.c