net/bnxt: fix flow flush to sync with flow destroy

net/bnxt: fix flow flush to sync with flow destroy

Sync flow flush routine with flow destroy so that the operations
performed per flow during a flush are the same as that are done for an
individual flow destroy by having a common function to call for both.
One of the things that was missed in the flow flush routine was the
deletion of the L2 filter that would have been created as part of an
n-tuple filter.
Also, decrement the l2_ref_cnt for a filter in the case of a filter
update as it would've bumped up previously in validate_and_parse_flow()

Fixes: 89278c59d97c ("net/bnxt: fix flow flush handling")
Cc: stable@dpdk.org
Signed-off-by: Somnath Kotur <somnath.kotur@broadcom.com>
Reviewed-by: Santoshkumar Karanappa Rastapur <santosh.rastapur@broadcom.com>