Fix issue 3425342.

Change the device selection order as follows to enable easier use of
A2DP while the device is docked:
1 - wired Headset
2 - A2DP Headset
3 - SPDIF/HDMI
4 - Dock

Also do not limit notifications volume when on dock.

Change-Id: I55ea6bea9f2d9ff284b54023e541b2788d0f1eb8