USB: gadget: atmel_usba_udc: fix transfer hang issue

When receive data, the RXRDY in status register set by hardware
after a new packet has been stored in the endpoint FIFO. After,
we copy from FIFO, we clear it, make the FIFO can be accessed
again.
In the receive_data() function, this bit RXRDY has been cleared.
So, after the receive_data() function return, this bit should
not be cleared again, or else it will cause the accessing FIFO
corrupt, which will make the data loss.

Signed-off-by: Bo Shen <voice.shen@atmel.com>

drivers/usb/gadget/atmel_usba_udc.c

@@ -1062,7 +1062,6 @@ static void usba_ep_irq(struct usba_udc *udc, struct usba_ep *ep)
 	if ((epstatus & epctrl) & USBA_RX_BK_RDY) {
 		DBG(DBG_BUS, "%s: RX data ready\n", ep->ep.name);
 		receive_data(ep);
-		usba_ep_writel(ep, CLR_STA, USBA_RX_BK_RDY);
 	}
 }