net/sched: Allow flower to match on GTP options

Options are as follows: PDU_TYPE:QFI and they refernce to
the fields from the  PDU Session Protocol. PDU Session data
is conveyed in GTP-U Extension Header.

GTP-U Extension Header is described in 3GPP TS 29.281.
PDU Session Protocol is described in 3GPP TS 38.415.

PDU_TYPE -  indicates the type of the PDU Session Information (4 bits)
QFI      -  QoS Flow Identifier (6 bits)

  # ip link add gtp_dev type gtp role sgsn
  # tc qdisc add dev gtp_dev ingress
  # tc filter add dev gtp_dev protocol ip parent ffff: \
      flower \
        enc_key_id 11 \
        gtp_opts 1:8/ff:ff \
      action mirred egress redirect dev eth0

Signed-off-by: Wojciech Drewek <wojciech.drewek@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>