scsi: csiostor: Return value not required for csio_dfs_destroy

Only csio_hw_free() calling csio_dfs_destroy() and it is not checking
return value. So remove the return from csio_dfs_destroy().

Link: https://lore.kernel.org/r/20191028194234.GA27848@sauravSigned-off-by: Saurav Girepunje <saurav.girepunje@gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/csiostor/csio_init.c

@@ -154,12 +154,10 @@ csio_dfs_create(struct csio_hw *hw)
 /*
  * csio_dfs_destroy - Destroys per-hw debugfs.
  */
-static int
+static void
 csio_dfs_destroy(struct csio_hw *hw)
 {
 	debugfs_remove_recursive(hw->debugfs_root);
-
-	return 0;
 }
 
 /*