drm/i915/display: remove struct drm_i915_private forward declaration

Remove unused struct drm_i915_private forward declaration from
intel_display_core.h. Sort and group forward declarations while at it.

Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://lore.kernel.org/r/fbccf45339a61711b377b35fd479a67b378c5571.1746529001.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Author: jnikula

drivers/gpu/drm/i915/display/intel_display_core.h

@@ -30,9 +30,6 @@
 #include "intel_pch.h"
 #include "intel_wm_types.h"
 
-struct task_struct;
-
-struct drm_i915_private;
 struct drm_property;
 struct drm_property_blob;
 struct i915_audio_component;
@@ -53,6 +50,7 @@ struct intel_hotplug_funcs;
 struct intel_initial_plane_config;
 struct intel_opregion;
 struct intel_overlay;
+struct task_struct;
 
 /* Amount of SAGV/QGV points, BSpec precisely defines this */
 #define I915_NUM_QGV_POINTS 8