drm/i915/display: add I915 conditional build to intel_sprite.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/b9680203b0b93dc3472260d7e4128984e533b421.1694514689.git.jani.nikula@intel.com

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

@@ -16,6 +16,7 @@ struct intel_crtc_state;
 struct intel_plane_state;
 enum pipe;
 
+#ifdef I915
 struct intel_plane *intel_sprite_plane_create(struct drm_i915_private *dev_priv,
 					      enum pipe pipe, int plane);
 int intel_sprite_set_colorkey_ioctl(struct drm_device *dev, void *data,
@@ -29,5 +30,12 @@ int hsw_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
 			const struct intel_plane_state *plane_state);
 int vlv_plane_min_cdclk(const struct intel_crtc_state *crtc_state,
 			const struct intel_plane_state *plane_state);
+#else
+static inline struct intel_plane *intel_sprite_plane_create(struct drm_i915_private *dev_priv,
+							    int pipe, int plane)
+{
+	return NULL;
+}
+#endif
 
 #endif /* __INTEL_SPRITE_H__ */