Add per-device startup config support

Add per-device startup config support

This change adds support for providing per-interface
parameters in the startup config.

Sample configuration:

  dpdk {
    dev default {
      num-rx-queues 3
      num-tx-queues 3
    }

    dev 0000:02:00.0 {
      num-rx-queues 2
      num-tx-queues 2
    }

    dev 0000:02:00.1
  }

Change-Id: Ia7d9ae2ac9c4fd9baaa480d061a395f8a421a722
Signed-off-by: Damjan Marion <[email protected]>