This is controlled by the writeback-mode when using AFRC, not by an YUV
Enable field. This Filed doesn't exist in these, and should according to
the spec be zero.
Fixes: 7a763bb0a3 ("pan/genxml: Rework the RT/ZS emission logic")
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Lars-Ivar Hesselberg Simonsen <lars-ivar.simonsen@arm.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/40489>