dm: fix the second dec_pending() argument in __split_and_process_bio()

Detected by sparse.

Fixes: 4e4cbee93d56 ("block: switch bios to blk_status_t")
Signed-off-by: Bart Van Assche <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Tested-by: Laurence Oberman <[e-mail]>
Signed-off-by: Mike Snitzer <[e-mail]>

drivers/md/dm.c

···
 	}
 
 	/* drop the extra reference count */
-	dec_pending(ci.io, error);
+	dec_pending(ci.io, errno_to_blk_status(error));
 }
 /*-----------------------------------------------------------------
  * CRUD END