Bluetooth:Aquire a wakelock to bring the display up.

Acquire a wakelock during PIN code request to bring up the LCD
display when the remote device requests for pairing.

CRs-fixed: 466069

Conflicts:
	src/com/android/bluetooth/btservice/RemoteDevices.java

Change-Id: I9c5f0f84b92d8d3f4224d7c5bd5cdc7dca0c2706
(cherry picked from commit 9f7587347a5aadf0411868c34c0a6149577c7398)
(cherry picked from commit f3f8ef02b58cb43e37fb0552b02cb86fd677ea7d)