net/bnxt: fix mark action if rule is at index zero

net/bnxt: fix mark action if rule is at index zero

In the ingress path, the cfa_code field in Rx completion identifies the
CFA action rule that was used for the incoming packet. It is possible
that the packet could hit the rule at index 0 in the table.
The mark action code was too restrictive by disallowing a cfa_code of
zero.
This code loosens the requirement and allows zero.

Fixes: b87abb2e55cb ("net/bnxt: support marking packet")
Cc: stable@dpdk.org
Signed-off-by: Mike Baucom <michael.baucom@broadcom.com>
Reviewed-by: Kishore Padmanabha <kishore.padmanabha@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>