In the CAIF Payload message the Packet Type indication must be set to
    UNCLASSIFIED in order to allow packet prioritization in the modem's
    network stack. Otherwise TCP-Ack is not prioritized in the modems
    transmit queue.
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>