Add support for setMiracastMode

Usage is setMiracastMode(WifiP2pManager.MIRACAST_SOURCE) or
setMiracastMode(WifiP2pManager.MIRACAST_SINK) as an example.
Only available for internal use and can be called as long as
driver is active. P2p connection is not needed for it to be
called

Bug: 8493089
Change-Id: I1f87eaf3311212aae980077de26c05651a8cc811