drm/xe/display: remove unused compat kdev_to_i915() and pdev_to_i915()

The display code no longer uses kdev_to_i915() or pdev_to_i915()
helpers. Remove them.
Reviewed-by: Gustavo Sousa <gustavo.sousa@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/05b948f9012fc7c0b97d567c70b0bac8791d554a.1724942754.git.jani.nikula@intel.comSigned-off-by: Jani Nikula <jani.nikula@intel.com>

drivers/gpu/drm/xe/compat-i915-headers/i915_drv.h

@@ -21,13 +21,6 @@ static inline struct drm_i915_private *to_i915(const struct drm_device *dev)
 	return container_of(dev, struct drm_i915_private, drm);
 }
 
-static inline struct drm_i915_private *kdev_to_i915(struct device *kdev)
-{
-	struct drm_device *drm = dev_get_drvdata(kdev);
-
-	return drm ? to_i915(drm) : NULL;
-}
-
 #define IS_PLATFORM(xe, x) ((xe)->info.platform == x)
 #define INTEL_INFO(dev_priv)	(&((dev_priv)->info))
 #define IS_I830(dev_priv)	(dev_priv && 0)
@@ -112,8 +105,6 @@ struct i915_sched_attr {
 };
 #define i915_gem_fence_wait_priority(fence, attr) do { (void) attr; } while (0)
 
-#define pdev_to_i915 pdev_to_xe_device
-
 #define FORCEWAKE_ALL XE_FORCEWAKE_ALL
 
 #ifdef CONFIG_ARM64