usb: musb: davinci.c: add missing unregister

usb_nop_xceiv_unregister is needed on failure of usb_get_transceiver, as
done in other error-handling code in the same function.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/musb/davinci.c b/drivers/usb/musb/davinci.c
index 97ab975..768b4b5 100644
--- a/drivers/usb/musb/davinci.c
+++ b/drivers/usb/musb/davinci.c
@@ -386,7 +386,7 @@
 	usb_nop_xceiv_register();
 	musb->xceiv = usb_get_transceiver();
 	if (!musb->xceiv)
-		return -ENODEV;
+		goto unregister;
 
 	musb->mregs += DAVINCI_BASE_OFFSET;
 
@@ -444,6 +444,7 @@
 
 fail:
 	usb_put_transceiver(musb->xceiv);
+unregister:
 	usb_nop_xceiv_unregister();
 	return -ENODEV;
 }