volume levels, in game - because sony didn't lol
install as "game"
/*
* game_volume - volume levels, in game
*
* This program is licensed under the GPL-v2 license.
* https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html
*
* code from PSP_HUD & ark-4
* https://github.com/ErikPshat/PSP-HUD
* https://github.com/PSP-Archive/ARK-4/
*/