configure_graphics: Add Accelerate ASTC decoding setting

src/yuzu/configuration/configure_graphics.h

@@ -47,6 +47,7 @@ private:
     QColor bg_color;
 
     ConfigurationShared::CheckState use_nvdec_emulation;
+    ConfigurationShared::CheckState accelerate_astc;
     ConfigurationShared::CheckState use_disk_shader_cache;
     ConfigurationShared::CheckState use_asynchronous_gpu_emulation;