For slightly unknown reasons, dsi0 takes a different pixel format
to dsi1, and that has to be set in the pixel valve.

Amend the setup accordingly.

Fixes: a86773d1 ("drm/vc4: Add support for feeding DSI encoders from the pixel valve.")
Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20220613144800.326124-14-maxime@cerno.techSigned-off-by: Maxime Ripard <maxime@cerno.tech>