net/bnxt: fix function id used in flow flush

net/bnxt: fix function id used in flow flush

The function id being used in the flush is incorrect, fixed the
flush of the flows.

Fixes: 74bcfc062489 ("net/bnxt: add session and function flow flush")
Cc: stable@dpdk.org
Signed-off-by: Kishore Padmanabha <kishore.padmanabha@broadcom.com>
Reviewed-by: Shahaji Bhosle <sbhosle@broadcom.com>
Reviewed-by: Ajit Khaparde <ajit.khaparde@broadcom.com>