Removing not needed OVS_BRIDGE_MAPPINGS check
Removing not needed OVS_BRIDGE_MAPPINGS check

As OVS_BRIDGE_MAPPINGS is mandatory for ovs-dpdk init
- removed not needed if statement
- removed one additional unary operator issue

Change-Id: Ia3c77dfcd3d973503b10f6a6f06663887b4a800e
Closes-bug: #1501649

stackforge/networking-ovs-dpdk,openstack/networking-ovs-dpdk,stackforge/networking-ovs-dpdk,stackforge/networking-ovs-dpdk,openstack/networking-ovs-dpdk