drm/vc4: hdmi: Use full range helper in csc functions

The CSC callbacks takes a boolean as an argument to tell whether we're
using the full range or limited range RGB.

However, with the upcoming YUV support, the logic will be a bit more
complex. In order to address this, let's make the callbacks take the
entire mode, and call our new helper to tell whether the full or limited
range RGB should be used.

Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-7-maxime@cerno.tech