Fix for Nyko playpad

Nyko playpad does not cmply with HID Device spec. NYKO gamepad
advertises as supporting virtual unplug but when virtual is sent
by host it responds with ERR_UNSUPPORTED_REQUEST. Modified BTIF
code to start a timer when VUP is issued and fire the timer if peer
does not respond.
Bug:8055549

Change-Id: I90db956fb243f1a518b00424b103ebf9f0a1b7f0