usb: renesas_usbhs: fixup: avoid NULL access on error case pipe detach

If renesas_usbhs or DMAEngine interrupt didn't happen by a certain cause,
urb->ep will be NULL by usb time out.
Then, host mode will access to it and crash kernel.
This patch fixes it.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/renesas_usbhs/mod_host.c

@@ -334,6 +334,11 @@ static void usbhsh_pipe_detach(struct usbhsh_hpriv *hpriv,
 	struct device *dev = usbhs_priv_to_dev(priv);
 	unsigned long flags;
 
+	if (unlikely(!uep)) {
+		dev_err(dev, "no uep\n");
+		return;
+	}
+
 	/********************  spin lock ********************/
 	usbhs_lock(priv, flags);