p2p: add p2p random MAC feature flag in framework

P2P random MAC needs the driver to support changing MAC address.

Bug: 118904478
Test: manual test
      * Enter WiFI Direct Page
      * check the feature is enabled in logcat
        * WifiP2pService: Supported feature: P2P MAC randomization
      * check p2p0 MAC address is randomized.

Change-Id: I189a984b27886ca009b5f269c848fa38faedf0d9