drm/vc4: plane: Allow using 0 as a pixel order value

vc4_plane_mode_set for HVS5 was using pixel_order unless pixel_order_hvs5
was non-zero, except 0 is a valid value for the pixel_order.

Specify pixel_order_hvs5 for all formats and remove the conditional.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
Link: https://lore.kernel.org/r/20221207-rpi-hvs-crtc-misc-v1-9-1f8e0770798b@cerno.tech


Signed-off-by: Maxime Ripard <maxime@cerno.tech>