HSI: omap_ssi_port: Don't print uninitialized err

Do not print err variable, that has nothing to do with the error.
This fixes a warning, that is printed at build time:

drivers/hsi/controllers/omap_ssi_port.c: In function ‘ssi_port_probe’:
drivers/hsi/controllers/omap_ssi_port.c:1121:10: warning: ‘err’ may be used uninitialized in this function [-Wuninitialized]
Signed-off-by: Sebastian Reichel <sre@kernel.org>

drivers/hsi/controllers/omap_ssi_port.c

@@ -1118,8 +1118,7 @@ static int __init ssi_port_probe(struct platform_device *pd)
 	dev_dbg(&pd->dev, "init ssi port...\n");
 
 	if (!try_module_get(ssi->owner)) {
-		dev_err(&pd->dev, "could not increment parent module refcount (err=%d)\n",
-			err);
+		dev_err(&pd->dev, "could not increment parent module refcount\n");
 		return -ENODEV;
 	}