py3: Fix ingress_bw_limit_for_dpdk_port() value conversion
py3: Fix ingress_bw_limit_for_dpdk_port() value conversion

Python 3 is not able to type int from string but max_bw_in_bytes is a
string in float format. This patch types first to float and then to int,
hence no ValueError is raised.

Change-Id: I7a527a58f79c1451d8593330d433f620cb0a4107
Closes-bug: #1771409

mahak/neutron,huntxu/neutron,huntxu/neutron,noironetworks/neutron,openstack/neutron,openstack/neutron,mahak/neutron,noironetworks/neutron,openstack/neutron,mahak/neutron