drm/i915/display: Copy color pipeline from plane in the primary joiner pipe

When copying plane color state in a joiner configuration, use the plane in
the primary joiner pipe since it carries the pipeline number selected by
the user-space.

This assumes that all pipes in the joiner are symmetric in their plane
color capabilities.

Cc: stable@vger.kernel.org # v6.19+
Fixes: a78f1b6 ("drm/i915/color: Add framework to program CSC")
Tested-by: Vidya Srinivas <vidya.srinivas@intel.com>
Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260511053213.3122314-2-chaitanya.kumar.borah@intel.com
(cherry picked from commit e8308fb)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>

Author: ckborah

drivers/gpu/drm/i915/display/intel_plane.c

@@ -373,7 +373,7 @@ intel_plane_color_copy_uapi_to_hw_state(struct intel_plane_state *plane_state,
 	bool changed = false;
 	int i = 0;
 
-	iter_colorop = plane_state->uapi.color_pipeline;
+	iter_colorop = from_plane_state->uapi.color_pipeline;
 
 	while (iter_colorop) {
 		for_each_new_colorop_in_state(state, colorop, new_colorop_state, i) {