drm/i915/display: add I915 conditional build to intel_lpe_audio.h

Add stubs for !I915.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/7c10d8c4a2a628cba17b3b0f89b657dfbc91eaa9.1694514689.git.jani.nikula@intel.com

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

@@ -12,11 +12,29 @@ enum port;
 enum transcoder;
 struct drm_i915_private;
 
+#ifdef I915
 int  intel_lpe_audio_init(struct drm_i915_private *dev_priv);
 void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv);
 void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv);
 void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
 			    enum transcoder cpu_transcoder, enum port port,
 			    const void *eld, int ls_clock, bool dp_output);
+#else
+static inline int intel_lpe_audio_init(struct drm_i915_private *dev_priv)
+{
+	return -ENODEV;
+}
+static inline void intel_lpe_audio_teardown(struct drm_i915_private *dev_priv)
+{
+}
+static inline void intel_lpe_audio_irq_handler(struct drm_i915_private *dev_priv)
+{
+}
+static inline void intel_lpe_audio_notify(struct drm_i915_private *dev_priv,
+					  enum transcoder cpu_transcoder, enum port port,
+					  const void *eld, int ls_clock, bool dp_output)
+{
+}
+#endif
 
 #endif /* __INTEL_LPE_AUDIO_H__ */