thunderbolt: Limit XDomain response copy to actual frame size

In the Linux kernel, the following vulnerability has been resolved: thunderbolt: Limit XDomain response copy to actual frame size tb_xdomain_copy() copies req->response_size bytes from the received packet buffer regardless of the actual frame size. When a short response arrives, this reads past the valid frame data in the DMA pool buffer into stale contents from previous transactions. Use the minimum of frame size and expected response size for the copy length.