mesa 20.2.0, vulkan not work on android 7
anv: downgrade common code for generating extensions to api25
https://github.com/youling257/mesa/commit/4f5a308704b56f0fda6586e654e8cdae3c9226df
anv: downgrade common code for generating extensions to api25
https://github.com/youling257/mesa/commit/4f5a308704b56f0fda6586e654e8cdae3c9226df