Adapts P2P settings to work with with new MAC privacy restrictions.

With change ag/7340724, the device's P2P MAC adress will no longer be
included as part of the WIFI_P2P_THIS_DEVICE_CHANGED_ACTION broadcast.
This change makes WifiP2pSettings request the device info after
receiving that broadcast, to make it aware of the device's MAC.

Bug: 132055766
Test: atest
/media/sdb1/android/packages/apps/Settings/tests/robotests/src/com/android/settings/wifi/p2p/
Test: Open Wi-Fi Direct settings, clear device name, observe that the
device's MAC is displayed.

Change-Id: I524afb0c8061c90cd775af422b542213cf14640a