[PATCH] drm/meson: Add zpos immutable property to planes

[Kevin Hilman]

Neil Armstrong <narmstrong at baylibre.com> writes:

> Add immutable zpos property to primary and overlay planes to specify
> the current fixed zpos position.
>
> Fixes: f9a2348196d1 ("drm/meson: Support Overlay plane for video rendering")
> Signed-off-by: Neil Armstrong <narmstrong at baylibre.com>

Reviewed-by: Kevin Hilman <khilman at baylibre.com>