Bluetooth: Acquire wakelock to turn on LCD for MAP authorization

This patch acquires a wakelock to turn on the LCD display if the screen
is off during an access request for MAP. Without this patch it was
observed that if the screen was off, the LCD remained off for incoming
connection access request from remote devices and the user only heard
the notification sound without the LDC being lit up.

Change-Id: I87c296fce4cd8e0c133f74169d991eee263fed08