Always queue A2DP connection state message with wakelock held

Messages for changes to A2DP connection state are intended to be
 queued in AudioService after acquiring a wake lock, which is
 released after the message has been handled.
This was correctly done for connection messages when the system
 is up and running, but wasn't when the BluetoothProfile service
 listener gets an onServiceConnected() event, which is the case
 the the device boots.
This change correctly uses the queueMsgUnderWakeLock() method
 whenever a MSG_SET_A2DP_CONNECTION_STATE is to be sent.

Bug 6616292

Change-Id: Ie337a4641a89c522e2d233bccaac4e08ce324117