dm9000: NULL dereferences on error in probe()

The dm9000_release_board() function is called with NULL ->data_req and
->addr_req pointers if dm9000_probe() fails.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/davicom/dm9000.c

@@ -817,10 +817,12 @@ dm9000_release_board(struct platform_device *pdev, struct board_info *db)
 
 	/* release the resources */
 
-	release_resource(db->data_req);
+	if (db->data_req)
+		release_resource(db->data_req);
 	kfree(db->data_req);
 
-	release_resource(db->addr_req);
+	if (db->addr_req)
+		release_resource(db->addr_req);
 	kfree(db->addr_req);
 }