mesa: gallium/dri Make YUV formats we're going to emulate external-only

This patch fixes the red label issues on video for Raspberry 4-64 Mesa VC4
driver and for iMX53 Adreno A200 GPU using the Mesa Freedreno driver.

Issue was originally reported in meta-webkit [1] and later contributed
in Mesa [2] where it was already merged in master.

[1] https://github.com/Igalia/meta-webkit/issues/185
[2] https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13038



Signed-off-by: Pablo Saavedra <psaavedra@igalia.com>
Signed-off-by: Anuj Mittal <anuj.mittal@intel.com>