usb: gadget: fsl: fix null pointer checking

fsl_ep_fifo_status() should return error if _ep->desc is null.

Fixes: 75eaa498 (“usb: gadget: Correct NULL pointer checking in fsl gadget”)
Reviewed-by: Peter Chen <peter.chen@nxp.com>
Signed-off-by: Ran Wang <ran.wang_1@nxp.com>
Signed-off-by: Felipe Balbi <balbi@kernel.org>

drivers/usb/gadget/udc/fsl_udc_core.c

@@ -1051,7 +1051,7 @@ static int fsl_ep_fifo_status(struct usb_ep *_ep)
 	u32 bitmask;
 	struct ep_queue_head *qh;
 
-	if (!_ep || _ep->desc || !(_ep->desc->bEndpointAddress&0xF))
+	if (!_ep || !_ep->desc || !(_ep->desc->bEndpointAddress&0xF))
 		return -ENODEV;
 
 	ep = container_of(_ep, struct fsl_ep, ep);