usb: musb: musb_dsps: request_irq() after initializing musb

If IRQ occurs between calling  dsps_setup_optional_vbus_irq()
and  dsps_create_musb_pdev(), then null pointer dereference occurs
since glue->musb wasn't initialized yet.

The patch puts initializing of neccesery data before registration
of the interrupt handler.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Nadezda Lutovinova <lutovinova@ispras.ru>
Link: https://lore.kernel.org/r/20210819163323.17714-1-lutovinova@ispras.ruSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/musb/musb_dsps.c

@@ -890,23 +890,22 @@ static int dsps_probe(struct platform_device *pdev)
 	if (!glue->usbss_base)
 		return -ENXIO;
 
-	if (usb_get_dr_mode(&pdev->dev) == USB_DR_MODE_PERIPHERAL) {
-		ret = dsps_setup_optional_vbus_irq(pdev, glue);
-		if (ret)
-			goto err_iounmap;
-	}
-
 	platform_set_drvdata(pdev, glue);
 	pm_runtime_enable(&pdev->dev);
 	ret = dsps_create_musb_pdev(glue, pdev);
 	if (ret)
 		goto err;
 
+	if (usb_get_dr_mode(&pdev->dev) == USB_DR_MODE_PERIPHERAL) {
+		ret = dsps_setup_optional_vbus_irq(pdev, glue);
+		if (ret)
+			goto err;
+	}
+
 	return 0;
 
 err:
 	pm_runtime_disable(&pdev->dev);
-err_iounmap:
 	iounmap(glue->usbss_base);
 	return ret;
 }