Remove audiohw_mute from header as well, and make this function static to each driver (commented out when it was unused) git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25733 a1c6a512-1295-4272-9138-f99709370657
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@23497 a1c6a512-1295-4272-9138-f99709370657
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21083 a1c6a512-1295-4272-9138-f99709370657