libstagefright: ACodec: Add missing message handling

Add kWhatSetParameters as a valid received message in state
OutputPortSettingsChangedState.
Without this fix, the mediaserver can end up in an endless loop
consuming significant extra cpu power.

Change-Id: I9719f1698bf411914eb753d3c349a15b9fbf9df6
Signed-off-by: Per Persson <per.persson@intel.com>
Signed-off-by: Persson, Mikael <mikael.persson@intel.com>
Signed-off-by: Fagerstedt, Axel <axel.fagerstedt@intel.com>
Signed-off-by: Yong Yao <yong.yao@intel.com>