The default volume can't be overlaid from xml.

Without headset or other extra devices, the volume will come
out from speaker of device. Then "*_speaker_volume" should be
stored into database, but there are no such items and the "*_volume"
can't work for default also. so we should add the corresponding
"*_speaker_volume" for customization.

Change-Id: Idb6bfcb9f02a48ae876d7ee7799fcb26f8c2b479
CRs-Fixed: 815661