opensles: remove external aout_get_native_sample_rate
opensles: remove external aout_get_native_sample_rate

Implement it directly in this module.
This avoid a dependency towards android libvlcjni.

xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc,xkfz007/vlc