camerad: make sure cl_context is valid for lifetime of camerad (#25735)

system/camerad/cameras/camera_common.cc

@@ -336,6 +336,7 @@ void camerad_thread() {
   cl_context context = CL_CHECK_ERR(clCreateContext(NULL, 1, &device_id, NULL, NULL, &err));
 #endif
 
+  {
     MultiCameraState cameras = {};
     VisionIpcServer vipc_server("camerad", device_id, context);
 
@@ -345,6 +346,7 @@ void camerad_thread() {
     vipc_server.start_listener();
 
     cameras_run(&cameras);
+  }
 
   CL_CHECK(clReleaseContext(context));
 }