drm/vc4: plane: YUV planes require vertical scaling to always be enabled

drm/vc4: plane: YUV planes require vertical scaling to always be enabled

It has been observed that a YUV422 unity scaled plane isn't displayed.
Enabling vertical scaling on the UV planes solves this. There is
already a similar clause to always enable horizontal scaling on the
UV planes.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20240621152055.4180873-16-dave.stevenson@raspberrypi.com
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>