net/bnxt: fix duplicate filter pattern creation error

If the attribute/pattern for a flow is the same, with only the 'action'
i.e the destination queue index changing, allow it by cleaning up
the older ntuple filter and updating the existing flow with
the new filter rule having the new destination queue ID.
Also, clear the L2 filter during flow_destroy after destroying
the ntuple filter, otherwise the flow record is not completely purged
from the HW.

Fixes: 5ef3b79fdfe6 ("net/bnxt: support flow filter ops")
Cc: stable@dpdk.org
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Signed-off-by: Ajit Khaparde <ajit.khaparde@broadcom.com>