usb: gadget: udc-xilinx: Fix an error handling path in 'xudc_probe()'

A successful 'clk_prepare_enable()' call should be balanced by a
corresponding 'clk_disable_unprepare()' call in the error handling path
of the probe, as already done in the remove function.

Fixes: 24749229 ("usb: gadget: udc-xilinx: Add clock support")
Reviewed-by: Shubhrajyoti Datta <shubhraj@xilinx.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/ec61a89b83ce34b53a3bdaacfd1413a9869cc608.1636302246.git.christophe.jaillet@wanadoo.frSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/gadget/udc/udc-xilinx.c

@@ -2136,7 +2136,7 @@ static int xudc_probe(struct platform_device *pdev)
 
 	ret = usb_add_gadget_udc(&pdev->dev, &udc->gadget);
 	if (ret)
-		goto fail;
+		goto err_disable_unprepare_clk;
 
 	udc->dev = &udc->gadget.dev;
 
@@ -2155,6 +2155,9 @@ static int xudc_probe(struct platform_device *pdev)
 		 udc->dma_enabled ? "with DMA" : "without DMA");
 
 	return 0;
+
+err_disable_unprepare_clk:
+	clk_disable_unprepare(udc->clk);
 fail:
 	dev_err(&pdev->dev, "probe failed, %d\n", ret);
 	return ret;