Fix possible NPE + and missing expandable panel

Steps to reproduce for NPE:
- go into volume style settings
- switch to disabled
- switch to expanded
- NPE and hotreboot

Fix:
Check if mStreamControls is initialized and if not lock it and do it.

Steps for expandable error:
- go into volume style settings
- switch to disable
- press one time the volume button
- change to expandable
- change the volume and press the expanded icon
- result is it does not expand and is empty due of the missing volume panels.

Fix:
- if it was changed from disabled to expanded be sure that the additional volume panels
are recreated.