I found one solution here:
https://dietpi.com/forum/t/optimizing-squeezelite-s-volume-control/1172/1
Squeezelite installed and added “-V Digital” to its config.
Now hardware volume control working fine from iPad/iPeng 
I found one solution here:
https://dietpi.com/forum/t/optimizing-squeezelite-s-volume-control/1172/1
Squeezelite installed and added “-V Digital” to its config.
Now hardware volume control working fine from iPad/iPeng