rtl8150: Use heap buffers for all register access

Allocating USB buffers on the stack is not portable, and no longer
works on x86_64 (with VMAP_STACK enabled as per default).

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
static int alloc_all_urbs(rtl8150_t * dev)
{
	dev->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->rx_urb)
		return 0;
	dev->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->tx_urb) {
		usb_free_urb(dev->rx_urb);
		return 0;
	}
	dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->intr_urb) {
		usb_free_urb(dev->rx_urb);
		usb_free_urb(dev->tx_urb);
		return 0;
	}

	return 1;
}

static int alloc_all_urbs(rtl8150_t * dev)
{
	dev->rx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->rx_urb)
		return 0;
	dev->tx_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->tx_urb) {
		usb_free_urb(dev->rx_urb);
		return 0;
	}
	dev->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!dev->intr_urb) {
		usb_free_urb(dev->rx_urb);
		usb_free_urb(dev->tx_urb);
		return 0;
	}

	return 1;
}
