greybus: es1: remove useless statement

just return the result of usb_alloc_urb up, no need to rededunt check for NULL
Signed-off-by: Rui Miguel Silva <rmfrfs@gmail.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/staging/greybus/gb-es1.c

@@ -180,8 +180,6 @@ static struct urb *next_free_urb(struct es1_ap_dev *es1, gfp_t gfp_mask)
 	dev_err(&es1->usb_dev->dev,
 		"No free CPort OUT urbs, having to dynamically allocate one!\n");
 	urb = usb_alloc_urb(0, gfp_mask);
-	if (!urb)
-		return NULL;
 
 	return urb;
 }