WiFiDisplayController: Defer the P2P Initialization from its constructor.

P2PManager initialization from WiFiDisplayController’s constructor
would start a p2p interface on the boot up when persist.debug.wfd.enable is set.
This would block the NAN operations if NAN and P2P concurrency is not
Supported.
Moreover , this initialization of P2P in WiFiDisplayController’s constructor is
Needless as this would be required for any of the P2P operations that would
happen at later point of time , based on the user’s trigger.
Thus , move this P2P initialization to the first action point of P2P operation
In WiFiDisplayController.

NOTE: Once initialization of P2P is done in WiFiDisplayController, it is not
de-initialized again. Thus P2P interface would exist and further NAN start would
fail until device is rebooted. This issue need to be fixed.

Change-Id: Ia26aee2f6496cf11aba3c99dcb55c3264ea0a5c0
CRs-Fixed: 2258826