USB: usbip: remove useless call in usbip_recv

Calling msg_data_left(&msg) is only useful for its return value,
which in this particular case is ignored.

Fix this by removing such call.

Addresses-Coverity-ID: 1427080
Fixes: 90120d15f4c3 ("usbip: prevent leaking socket pointer address in messages")
Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/usbip/usbip_common.c

@@ -325,7 +325,6 @@ int usbip_recv(struct socket *sock, void *buf, int size)
 	usbip_dbg_xmit("enter\n");
 
 	do {
-		msg_data_left(&msg);
 		sock->sk->sk_allocation = GFP_NOIO;
 
 		result = sock_recvmsg(sock, &msg, MSG_WAITALL);