usb: gadget: aspeed: fix typo

Fix spelling mistake: "lenght" -> "length"
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

drivers/usb/gadget/udc/aspeed-vhub/epn.c

@@ -120,7 +120,7 @@ static void ast_vhub_epn_handle_ack(struct ast_vhub_ep *ep)
 	/* No current DMA ongoing */
 	req->active = false;
 
-	/* Grab lenght out of HW */
+	/* Grab length out of HW */
 	len = VHUB_EP_DMA_TX_SIZE(stat);
 
 	/* If not using DMA, copy data out if needed */