dmaengine: sdxi: completion: Forward-declare struct sdxi_desc

For sdxi_completion_attach().

Signed-off-by: Nathan Lynch <nathan.lynch@amd.com>

Author: nathanlynch

drivers/dma/sdxi/completion.h

@@ -10,6 +10,7 @@
  * descriptor.
  */
 struct sdxi_completion;
+struct sdxi_desc;
 struct sdxi_completion *sdxi_completion_alloc(struct sdxi_dev *sdxi);
 void sdxi_completion_free(struct sdxi_completion *sc);
 void sdxi_completion_poll(const struct sdxi_completion *sc);