drm/i915/display: Move releasing gem object away from fb tracking

As a preparation for Xe we want to remove all i915_gem_object details away
from frontbuffer tacking code. Due to this move releasing gem object
reference to i915_gem_object_set_frontbuffer.
Signed-off-by: Jouni Högander <jouni.hogander@intel.com>
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231012072158.4115795-2-jouni.hogander@intel.com

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

@@ -265,8 +265,6 @@ static void frontbuffer_release(struct kref *ref)
 	spin_unlock(&intel_bo_to_i915(obj)->display.fb_tracking.lock);
 
 	i915_active_fini(&front->write);
-
-	i915_gem_object_put(obj);
 	kfree_rcu(front, rcu);
 }
 

drivers/gpu/drm/i915/gem/i915_gem_object_frontbuffer.h

@@ -89,6 +89,7 @@ i915_gem_object_set_frontbuffer(struct drm_i915_gem_object *obj,
 
 	if (!front) {
 		RCU_INIT_POINTER(obj->frontbuffer, NULL);
+		drm_gem_object_put(intel_bo_to_drm_bo(obj));
 	} else if (rcu_access_pointer(obj->frontbuffer)) {
 		cur = rcu_dereference_protected(obj->frontbuffer, true);
 		kref_get(&cur->ref);