net/enic: allow flow mark ID 0

net/enic: allow flow mark ID 0

The driver currently accepts mark ID 0 but does not report it in
matching packet's mbuf. For example, the following testpmd command
succeeds. But, the mbuf of a matching IPv4 UDP packet does not have
PKT_RX_FDIR_ID set.

flow create 0 ingress pattern ... actions mark id 0 / queue index 0 / end

The problem has to do with mapping mark IDs (32-bit) to NIC filter
IDs. Filter ID is currently 16-bit, so values greater than 0xffff are
rejected. The firmware reserves filter ID 0 for filters that do not
mark (e.g. steer w/o mark). And, the driver reserves 0xffff for the
flag action. This leaves 1...0xfffe for app use.

It is possible to simply reject mark ID 0 as unsupported. But, 0 is
commonly used (e.g. OVS-DPDK and VPP). So, when adding a filter, set
filter ID = mark ID + 1 to support mark ID 0. The receive handler
subtracts 1 from filter ID to get back the original mark ID.

Fixes: dfbd6a9cb504 ("net/enic: extend flow director support for 1300 series")
Cc: stable@dpdk.org
Signed-off-by: Hyong Youb Kim <hyonkim@cisco.com>
Reviewed-by: John Daley <johndale@cisco.com>