DockAudio: Always route audio back to normal on undock.

Only ignore dock event when docking, not undocking.

Previously for Samsung devices that utilize the extra setting to enable
the dock audio, if the device setting is disabled while on the dock, audio
is prevented from routing back to the device speaker after undocking.

Change-Id: Ib182751a29bf7ba8feb9ff153cd3708df80f7ee6