Revert "Bluetooth: Connect only A2dp Sink devices."

This reverts commit c86e8fac.

At least my car stereo doesn't properly advertise its device class as
BluetoothClass.Device.AUDIO_VIDEO_CAR_AUDIO, but has its device class
set to BluetoothClass.Device.Major.UNCATEGORIZED instead. As I highly
doubt it's the only working A2DP device in the world that does that, the
check seems too strict.

Change-Id: Ic341cf7af290ede87132f396b00afa9030076c18