adjust device volume when launching xbmc

Pivos has a commit that sets the device volume to max when launching XBMC. Mainly designed for set-top-boxes where something sets the android device low and since XBMC's volume is based off the device volume, you can't hear anything and as a side effect, ac3/dts passthough would break

See https://github.com/Pivosgroup/xbmc/commi...dc40e55d8d

Is this something we want in mainline ?