[Mesa-stable] Wayland format fixes for stable branches

[Emil Velikov]

Hi all,

AFAICT the following two patches are a must have if we're interested
in properly working PRIME with the new color depth 30 formats.
Mario, others what do you thing?

Thanks
Emil

a34b0d68bbf egl/wayland: Allow client->server format conversion for
PRIME offload. (v2)
820dfcea431 egl/wayland-drm: Only announce formats via wl_drm which
the driver supports.