usb: dwc3: core: only setting the dma_mask when needed

If the probe drivers have already set the dma_mask, not
replacing the value.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.c

@@ -715,9 +715,11 @@ static int dwc3_probe(struct platform_device *pdev)
 	spin_lock_init(&dwc->lock);
 	platform_set_drvdata(pdev, dwc);
 
+	if (!dev->dma_mask) {
 		dev->dma_mask = dev->parent->dma_mask;
 		dev->dma_parms = dev->parent->dma_parms;
 		dma_set_coherent_mask(dev, dev->parent->coherent_dma_mask);
+	}
 
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);