staging: usbip: Fix format string mismatch in usbip_vhci_attach_device2

Argument type of sockfd is set as int, but format string
is set as unsigned int. Fix the mismatch.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/usbip/userspace/libsrc/vhci_driver.c

@@ -545,7 +545,7 @@ int usbip_vhci_attach_device2(uint8_t port, int sockfd, uint32_t devid,
 		return -1;
 	}
 
-	snprintf(buff, sizeof(buff), "%u %u %u %u",
+	snprintf(buff, sizeof(buff), "%u %d %u %u",
 			port, sockfd, devid, speed);
 	dbg("writing: %s", buff);